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Full text of "How an aeroplane is built"

TL 

671.2 
B6 

1918X 
IULSH 



m s 



E. P. Warner. 



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THE AERONAUTIC LIBRARY INC. 

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HOW AN AEROPLANE IS BUILT 



A 



Chow an aeroplane 



is BUILT 



BY 

STEPNEY BLAKENEY 



With an Introduction 

BY 

C. G. GREY 




LONDON : 

"AEROPLANE " & GENERAL PUBLISHING CO., Ltd., 
Rolls House, Bream's Buildings, Chancery Lane E.C. 



SECOND EDITION 



CONTENTS 



PAGE 

INTRODUCTORY . . . • • -9 
I. POINTS OT ORGANISATION FOR GENERAL 

MANAGERS, WORKS MANAGERS, AND OTHER 

OFFICIALS . . ■ • .16 

II. GETTING TO WORK . . . .35 

III. ERECTING THE FUSELAGE . . .65 

IV. WING STRUCTURE . . . .76 
V. WING COVERING .... 100 

VI. DOPING . . • . 102 

VII. AILERON CONSTRUCTION . .104 

VIII. THE MANUFACTURE OF METAL FITTINGS . 113 

IX. BOLT MAKING . . . . .124 

X. LIFT PLATES . . . . .132 

XI. THE TAIL PLANE . . . .140 

XII. CONTROL LEVERS . . . .147 

XIII. TAIL-SKID FITTINGS . . . .149 

XIV. STRUT-END FITTINGS . . . .156 
XV. ENGINE PLATES . . . .163 

XVI. PETROL TANKS . . . .168 

XVII. CASTLE NUTS AND THEIR MANUFACTURE . 177 

XVIII. COMPLETING THE CENTRE SECTION . .183 

XIX. DOPING, VARNISHING AND PIGMENTING . 187 

XX. THE FINISHED PARTS, STORES, AND THE 

ASSEMBLING SHOP . . .191 

XXI. ERECTING THE MACHINES . . .195 

XXII. CHECKING THE ANGLES OF THE WINGS . 208 
XXTII. ATTACHING AUXILIARY SURFACES. MOUNTING 

THE TAIL UNIT . . . .217 

XXIV. FINAL CHECKING . . ■ .220 

XXV. ODD JOBS AND GENERAL EXAMINATION • 225 



ILLUSTRATIONS 



PAGE 

RIFT SAWN TIMBER . . . . .36 

CUTTING LONGERONS . . . . .37 

TAPERING LONGERONS - . . . .38 

STRUTS BEFORE AND AFTER TAPERING . . 42 

ASH FUSELAGE STRUTS . . . .45 

ASH FUSELAGE SPAR - . . . .47 

BOX JIG FOR SPINDLING STRUTS . . .50 

FUSELAGE JIG AND COMPLETE PORTION . . 57 

LENGTH GAUGE . , . . .61 

SECTIONAL ELEVATION OF JIG AND FUSELAGE . . 66 

FRONT PORTION OF FUSELAGE JIG . . .67 

RIB JIG . . • . . .81 

the leading edge . . . . .86 

centre section . • ■ . .87 

lightening in spars . . • . .93 

wing construction . . . . .95 

plan of an aileron . . . .109 

drilling jig . . . ■ . • 121 

holders and drill chuck . . . .127 

spar attachment . . ■ . .137 

steel formers . • ■ ■ .144 

skid fork in jig ... . 150 

jig for boring skid fork socket . . .152 

strut shoe in place . . . .154 

attachment of strut to spar . . .157 

Types of metal fittings i. . . . .111 

types of metal fittings ii. , . .139 

Types of metal fittings hi. . . . .159 

cable Testing machine . . . .176 

jig for holding nuts to be slotted . .178 

milling jig . . • • • .180 

drilling jig . . • • • .181 

fabric and needle . ■ . .185 

stream line wire with fork joint . .204 

side view of Tractor biplane . . 209 

front view of tractor biplane . .211 



HOW AN AEROPLANE 
IS BUILT 




INTRODUCTORY. 

By C. G. GREY, Editor of The 
Aeroplane. 

This little book, which in its original form 
appeared as a series of articles in The 
Aeroplane, was written by Mr. Stepney 
Blakeney at my request, as the result of 
various entertaining conversations on 
methods of aeroplane construction. Mr. 
Blakeney showed such an intimate know- 
ledge of detail work, as well as of workshop 
lay-out and organisation, that it appeared 
the right thing to use some of that know- 
ledge for the benefit of the uninitiated. 

The book does not profess to be a learned 
dissertation on factory methods, nor a 
series of hints and tips on aeroplane con- 
struction. It is intended to show in the 
simplest possible language the way in 
which a smallish firm, suddenly turned on 
to produce aeroplanes of an ordinary 
standard type, might set about the job with 
reasonable prospects of success. 




HOW AN AEROPLANE IS BUILT 



FOE THE FACTORY WORKER. 

In these days there are hundreds of thou- 
sands of men and women engaged in 
making aeroplane parts. Very few of them 
know whereabouts in an aeroplane the part 
on which they are working is intended to 
go, or what it is intended to do when it gets 
there. Yet many of them would like to 
know, and would take a keener interest in 
their work if they understood the why and 
wherefor thereof. This book will give such 
intelligent people a fair understanding of 
the reason for their work and of its im- 
portance in the complete aeroplane. 

FOR THE DRAUGHTSMAN. 

In drawing offices, also, there are many 
hundreds of fairly well educated men and 
women, who, though they may be excellent 
hands at drawing and tracing, have no 
opportunity of going into the workshops 
and seeing how the work is done to their 
drawings, or of seeing what the finished 
component part looks like before it is put 
into its place in the machine. Many of 
them, indeed, are so new to aeroplane 
work that they could not even locate in a 
General Arrangement Drawing the precise 
place where the component part which 
they have been drawing is intended to fit. 
They merely work to instructions, without 
intelligent appreciation of the reasons for 



HOW AN AERO PLANE IS BUILT 
those instructions. Such people, also, will 
be able to acquire from Mr. Blakeney's 
description an all-round idea of how the 
parts of an aeroplane are made, and how 
they come together to form a complete 
machine, and it is hoped that this know- 
ledge will help them to find their work 
more interesting. 

FOR THE MERELY INTERESTED. 

Over and above the people in aircraft 
factories there are many thousands of 
others who are keenly interested in aero- 
planes, and who, having a natural liking 
for things mechanical, are anxious to know 
by what general methods so much timber 
and metal is turned into a modern flying 
machine. These seekers after information 
will find in this book a simple and easily 
understandable account of the whole pro- 
cess of manufacture, from the rough plank 
and the metal sheet to the complete aero- 
plane ready to make its trial flight. 

FOR THE SCHOOLBOY. 

One believes, also, that in these days 
when every youngster at school desires to 
become an aviator, just as in my young 
days we aspired to be engine-drivers- 
motor-cars and aeroplanes being then un- 
discovered — Mr. Blakeney's simple de- 
scriptions of the various workshop pro- 
cesses which go to make an aeroplane will 
i'4 



HOW AN AEROPLANE IS BUILT 
be highly appreciated by school-boys of 
the age at which they begin to study the 
motoring and flying papers. 

A GENERAL IDEA. 

It must not be thought that Mr. 
Blakeney's imaginary workshop represents 
the last word in the development of aircraft 
factory development. It is, as he points 
out, a small shop employing a hundred 
hands or so, and he has laid down its 
organisation so that it may be capable of 
expansion to any extent desired. It stands, 
in fact, in the safe middle position between 
the old aerodrome shed, in which we used 
to build our aeroplanes some seven or eight 
years ago, and the kind of aeronautical 
sausage factory which will produce the 
Aerial Fords of the future. Therefore the 
digestion of the book may be regarded as 
an easily comprehensible undertaking for 
any intelligent person who is keen on aero- 
planes, and who wants to learn in a general 
way how they are produced. 

THE AUTHOR'S QUALIFICATIONS. 

As to Mr. Blakeney's qualifications to 
write on the subject of aircraft workshop, 
I should like to point out that for nearly 
20 years before the war he was a rail- 
way engineer. He served his time in 
the locomotive shops, which is the best 
training any engineer can have. Loco 

12 



HOW AN AE ROPLANE IS BUILT 
engineers are like the British workman's 
opinion of beer : " There's no bad beer, 
but some kinds are better than others." 
Likewise there are no bad loco engineers, 
but some are better than others. 

After doing loco work in the shops Mr. 
Blakeney went right through the railway 
business, driving, plate-laying, ballasting, 
making cuttings and embankments, build- 
ing stations, and all the rest of it, so that 
he is a constructional engineer as well as a 
workshop manager. 

PRACTICAL DEMONSTRATION. 

Also I can vouch for the fact that he 
is himself a first-class machine-hand and 
fitter, who can take off his coat and show 
any man in the shop how his job ought to 
be done. I have known him, when a man 
has grumbled over a piecework price, 
hand the man his watch to check the time 
on the job, and then set about it to such a 
tune that he showed the man on the man's 
own timing that he was being paid just 
twice as much as the job was worth, if only 
he would take the trouble to do the job the 
right way. 

THE TEACHING- Of EXPERIENCE. 

Early in the war Mr. Blakeney left the 
railway and went to a well-known aircraft 
factory, where he laid down the machine 
tools in a new machine-shop ; designed, 

'3 



HOW AN AEROPLANE IS BUILT 
bought the material for, and superintended 
the erection of a whole new section of the 
works ; reorganised the whole output, and 
raised it to a rate which had never been 
thought possible, and generally did the 
firm much good. Since then he has been to 
certain other firms, each job being a step 
upward in responsibility, and at each he 
has added to his knowledge of the problems 
of organising an aircraft factory, for at 
each he has had to evolve order out of 
chaos. And as witness to his success in 
handling men, it is worth noting that when- 
ever he has left a firm to go to another the 
men under him have clubbed together to 
present him with some testimonial or other 
of their esteem and regard for a boss who 
has always given them a square deal. 
Therefore I submit that he is entitled to be 
accepted as understanding that about 
which he has written. 

THE PUBLIC DEMAND. 

While the articles were running in The 
A eroplane, letters were constantly coming 
in from people in all classes, from man- 
agers of works who had recently been 
turned onto aircraft production, from 
mechanics, from women munition workers 
of the better class, from draughtsmen, and 
from school-boys, all anxious to know 
whether, and if so when, the series would be 
published in book form. It is now at their 
14 



HOW AN AEROPLANE IS BUILT 
disposal, revised in detail, with fresh draw- 
ings, and many more of them, by Mr. 
Geoffrey Watson, one of the most accurate 
and descriptive of aircraft artists. 

A PROPAGANDIST WORK. 

If these readers like the book I hope 
they will recommend it to their friends, 
and will so help to spread the interest in 
aviation which is so necessary if, after the 
war, the Government is to be forced by 
public opinion to maintain the huge Air 
Fleet which will be necessary to our future 
freedom from foreign domination. Mr. 
Blakeney's descriptions will show that an 
aeroplane, with its thousands of parts and 
hundreds of thousands of operations, 
cannot be built in a day. How much more 
necessary is it, therefore, to maintain after 
the war a strong and healthy Aircraft 
Industry, which will be able to supply the 
Air Force with all the aeroplanes it will 
need whenever it may need them? 

Those in search of a moral will find that 
such is the moral of this little book. Those 
who are not interested in morals will, I am 
sure, find it very informative and in- 
teresting reading. 

C. G. G. 



CHAPTER 1 



POINTS OF ORGANISATION FOR GENERAL 
MANAGERS, WORKS MANAGERS, AND 
OTHER OFFICIALS. 

In introducing the subject of the produc- 
tion of aeroplanes and their components it 
is necessary for those who have no experi- 
ence in the Aircraft Industry that they 
should be given a slight insight into the 
works' organisation required, to enable 
them to grasp the fundamental principles 
and realise what position their abilities will 
permit them to hold. One can only be a 
general manager in name if one cannot 
manage, and this remark applies to all con- 
cerned holding lower grade positions. 

Let it be assumed that a small but pro- 
gressive and enterprising engineering firm 
are about to take up aircraft work. If the 
head of the firm is a practical man, who has 
given the subject of aircraft production 
considerable thought, which is very neces- 
sary before entering into this industry, he 
will have had to consider many difficult 
points in connection with this class of work. 

POINTS TO BE STUDIED. 
The principal points to be studied may 
be summarised as follows: — (a) The suit- 

16 



HOW AN AEROPLANE IS BUILT 



ability of his works and premises, (b) The 
suitability of existing machinery, (c) The 
purchase of additional new plant and tools, 
(d) The estimating for new contracts, (e) 
The placing of orders for raw materials. 

(f) The date for its delivery in and out. 

(g) The capabilities of his existing staff. 

(h) Their selection for various duties, (i) 
Whether it will be necessary to introduce 
a few experienced men to act as instruc- 
tors, (j) The proportion of metal to wood 
workers necessary, (k) The utilisation of 
female labour, and accommodation for 
women workers. (1) The storage of timber 
and steel, (m) The arrangement of raw 
material stores, (n) The planning, pro- 
gress, and inspection departments, (o) The 
finished parts, and methods of delivery. 

Having enumerated the principal points, 
it will be well worth while to consider some 
of them in detail. 

The works will now have, to a large 
extent, to be cleared of all previously used 
material, and possibly rearranged, and I 
would suggest that the simple process of 
window-cleaning be vigorously carried out, 
as it will probably cause many a scrap heap 
to come to light, and will enable the new 
work to be started under good conditions. 

The workshops that are to be used for 
aircraft work should now be selected ac- 
cording to their adaptability for the work 
that is to be done in them. 

17 

B 



HOW AN AEROPLANE IS BUILT 



THE ERECTING OR ASSEMBLING SHOP. 

Naturally, the largest shop will be 
utilised for an erecting shop, that is to say, 
if the entrance is conveniently situated and 
arranged for large cases of goods being 
brought in or taken out for loading into 
lorries. 

Headroom is also an important item if 
machines are likely at any time to be 
erected here, 16 ft. being a convenient 
height. It is also frequently useful if a steel 
joist runway is fitted up in a portion of this 
shop, as it enables engines to be easily 
handled and put into machines, and it is 
also useful as a means of attachment for 
weighing machines. 

THE FITTING SHOP. 
The fitting shop is the next shop that 
ought to be considered, for it is one of the 
first shops that should be equipped and 
started, as metal work takes a surprisingly 
long time to produce. Of course, many 
people will tell you it can be made very 
quickly and easily, but I have generally 
found that the first consignment of the 
" quickly and easily made " variety usually 
finds its way to the scrap heap quickly and 
easily. 

Light and the arrangement of the 
benches should be carefully considered, 
as it is here that the largest amount of 
supervision is required, especially if the 
18 



HOW AN AEROPLANE IS BUILT 
hands are new at the work. The equip- | 
ment should consist of 4J-in. vices mounted I 
on strong benches, about 4 ft. 6 in. apart, | 
with one cast iron chipping block, 10 in. I 
by 10 in. by 2 in. thick, to each three men. | 
In addition there should be a metal jigsaw, I 
with at least half a dozen 10-ft. coils of I 
^-in. wide metal jigsaw blades ; a quick- 1 
work shearing machine with rotating cut- 
ters — power driven preferably; a 36-in. 
guillotine to cut up to 8 gauge steel sheet— 
power driven ; a set of rolls for sheet metal 
work; one 7-in.-bladed hand shearing, 
machine ; one sensitive drilling machine to; 
take J-in. twist drills ; and an annealing 
furnace of moderate size, with a pyro- 
meter, gas-fired preferably ; also an acety- 
lene welding plant for one or two opera- 
tors. 

This plant should be sufficient outfit for 
10 to 20 workers where rapid production 
on small contracts is essential. 

THE METAL MACHINE SHOP. 
The metal machine shop should next be 
considered. This should be equipped with 
6^-in. centre precision lathes with self- 
centring and independent chucks ; f-in. 
and f-in. capstan lathes, and one lj-in. 
capstan lathe, all preferably with lever 
feed, and six adjustable stops ; a couple of 
good plain milling machines ; a vertical 
milling machine, and a dividing head ; a 
19 



HOW AN AEROPLAN E IS BUILT 
tapping machine ; an emery grinder and 
disc grinder ; a universal cutter grinder ; a 
couple of sensitive drills ; and a good plain 
drilling machine to take up to -f-in. drills. 
Also a 13-in. shaper is essential. A 10 or 
20 ton power press is useful, as also is a 
heavy fly press. 

The whole will be driven by the most 
convenient power available, and, where 
possible, will be placed on solid founda- 
tions, this being a matter of considerable 
importance for aircraft work. 

THE SAWMILL OR WOOD MACHINE SHOP. 

The sawmill should next be equipped. 
For breaking up large timber, a 36-in. saw 
is useful. There will also be an 18-in. 
circular saw ; an overhand planing ma- 
chine ; a thicknessing machine ; three 
vertical spindles with a speed not under 
5,000 revs, per minute ; a bandsaw ; a jig- 
saw ; a grinding machine for plane irons ; 
a brazing apparatus for bandsaws ; a disc 
sand-papering machine ; and a horizontal 
sand-papering machine. A four-cutter is, 
of course, very useful also. Also a sensitive 
drilling machine, complete with wood 
drills. 

This plant will be driven preferably with 
20 per cent, excess of the power required, 
so as to have a good margin in case of an 
overload. 

The placing of the machines in the saw- 

20 



HOW AN AEROPLANE IS BUILT 
mill should receive careful attention, andj 
it is advantageous to lay out the machines! 
on paper before they are fixed, as the longs 
lengths of timber worked may cause con-j 
siderable inconvenience when all thej 
machines are working at once, and a con-j 
siderable fall off in output will occur. 

THE WOOD-WORKING SHOP. 
The wood-working shop does not require 
much beyond the ordinary joiners' 
benches, except a few spar and longeron 
benches, which should be about 20 ft. long 
by 2 ft. wide to enable two joiners to work 
on them on each side. There should also 
be a drilling machine ; a good grindstone 
for the wood-workers' tools ; a steam box 
for wood bends ; a gas-heater for glue pots ; 
a large setting out table, 12 ft. by 6 ft., and 
glueing cramps on benches for hollow spar 
work. 

THE DOPE SHOP AND COVERING SHOP. 

The dope shop is a shop which requires 
special attention on account of the fumes 
which have to be removed. Reference 
should be made to the Home Office regula- 
tions. Also, heat is an important matter, 
and the heating apparatus must have ample 
proportions if delay in doping is not to 
occur. 

The covering shop does not call for any 
special consideration beyond size, dryness 



HOW AN AEROPLANE IS BUILT 

and cleanliness, and close proximity to the 
dope shop. 

THE RAW METAL STORE. 
The raw metal stores should be of ample 
proportions, with at least a 30 per cent, 
margin for expansion. To commence 
with, 300 Sankey bins, 14 in. by 14 in. by 
14 in., are useful. These should, for pre- 
ference, be built up in portable sections, 
double-sided, about 6 ft. by 6 ft. by 2 ft. 
5 in. 

Tubes and steel rods and bars can best 
be stored in a vertical position, where 
head room permits, with short vertical 
racks for short lengths. 

Sheet steel should stand in vertical racks, 
arranged according to the gauge. 

THE TIMBER STORE. 
The timber store should next have at- 
tention. The site should be as close to the 
point of delivery as possible, and this again 
should be conveniently adjacent to the 
sawmill, otherwise valuable time and 
money will be lost in handling the large 
timber. 

To prevent unsuitable timber from being 
cut up for component parts, it is best for 
someone who has had experience with the 
selection and conversion of timber into 
aircraft parts to examine the timber and 
superintend the stacking of all timber with 

22 



HOW AN AEROPLANE IS BUILT 



suitable grain and quality in piles, accord-J 
ing to its suitability of grain for the various! 
parts required in aircraft work. A notice j 
should be nailed on a board, attached to 
each pile, specifically stating for what pur- 
pose each pile of timber is most suitable. 
This simple organisation will probably 
save the firm pounds, and also possibly 
their reputation. 

The timber shed should be dry and airy, f 
and all timber should be at least 9 in. off 
the ground, laid flat, and with frequent 
distance pieces of packing between each 
plank to admit of a free circulation of air 
between, care being taken to space the 
pieces out evenly. 

ENSURING ACCURACY. 

The fine limits of dimensions in aircraft 
work necessitate the machinery being in 
an accurate working condition, and a 
thorough examination of it is necessary. 
Inaccurate machines must be made 
accurate or scrapped, those not suit- 
able being replaced by machines that 
are. This will involve promptly se- 
lecting and ordering the new ma- 
chinery required. The firm will also 
require micrometers ; a couple of steel 
tapes ; wire gauges ; protractors ; and 
flexible steel rules, preferably marked in 
decimals and millimetres. 

23 



HOW AN AEROPLANE IS BUILT 



ORDERING MATERIAL. 

The special steel required, both sheet 
and bar, nuts, bolts, etc., must be now 
ordered and obtained. These must be 
strictly in accordance with the specifica- 
tion mentioned, and should be ordered by 
the planning department after a careful 
examination of each plan of component 
parts, and the list checked. 

The timber required should also be 
ordered, and a selection by a competent 
specialist made before delivery. 

SELECTION OF STAFF. 
The selection of the staff for the various 
departments and posts therein will require 
I careful consideration. The first men to be 
| selected should be for the planning or 
| organising department. 
I These men should be trained draughts- 
men, who preferably have had workshop 
| training, as they must be capable of read- 
ing a drawing and producing one, together 
with dimensioned sketches of parts re- 
quired, and drawings of the necessary 
jigs. These men can, with advantage, be 
divided into four groups, namely, those 
experienced in metal working, those ex- 
perienced in wood work, and those ex- 
perienced in tool and jig work. 

One or two others with a fair general 
knowledge will be allocated to the duty of 
24 



HOW AN AEROPLANE IS B UILT 
recording the works' production orders 
issued to the works ; the drawings accom- 
panying them, and the date on which 
these are issued ; ascertaining the date on 
which production should commence ; and 
reporting each day to the manager those 
items on which production is not in ac- 
cordance with the schedule of parts re- 
quired. 

This system, if carefully organised and 
rigidly carried out, will be found to be of 
the greatest possible value to all con- 
cerned in production, and will prevent 
delay in the erecting and other shops. 
Thus, it may be looked upon as a valuable 
step towards rapid production, as those 
items which are behind time will at once 
have the attention of the manager and the 
foremen. These officials will scrutinise 
the cause of delay, and the method of 
production, and, if necessary, will change 
it at the earliest moment or remedy the 
material which may be faulty, or alter the 
jigs, and thus prevent " scrap " from being 
made. 

FITTING SHOP PERSONNEL. 

The foreman of the fitting shop should 
next be selected. He should be chosen 
for his superior knowledge of metal work- 
ing, his appreciation of accuracy in detail, 
and, if possible, his ability for reading 
drawings correctly, together with his 



HOW AN AEROPLANE IS BUILT 
faculty for leading his men, and control- 
ling their methods. Under his control 
should be placed a first-class marker-off, 
whose duty will be to mark off accurately 
all templates on black iron sheet, or other 
available metal. When he has set to work 
press tools can be put in hand if the quan- 
tity of aeroplane fittings required is suffi- 
ciently large. With this man, a first- 
class template maker should be set to 
work, whose duty it will be to produce 
truly and accurately all templates for 
sheet metal parts that have to be made, 
and a tool maker for making drilling and 
other jigs. 

These, when completed, should be 
carefully checked by the inspection depart- 
ment and stamped. They will then be ready 
for the use of semi-skilled hands, who will 
roughly cut out and finish off the sheet 
metal parts, which will then be passed 
on to the skilled metal workers to com- 
plete. 

ARRANGEMENT OF HANDS. 

The skilled metal workers should next 
be selected. These men, being trusted 
workers, may, with advantage to the fore- 
man, be placed in the part of the shop 
which is most difficult for him to super- 
vise. Near them should be placed the 
bench for the best of the unskilled 
workers, and close to the foreman's office, 
26 



HOW AN AEROPLANE IS BUILT 

or in the part of the shop most accessible 
for supervision, should be placed those 
workers who have the least experience. 
This system has been tried and has given 
excellent results, and can be recom- 
mended for a trial. 

Female labour should preferably work 
in a separate part of the shop, there being 
many jobs, such as bending wiring plates, 
stamping the drawing number and part 
numbers, cleaning off scale after anneal- 
ing, cleaning up castings, rough riling 
small light-gauge parts to a plus size tem- 
plate, which can be undertaken by them 
with success, also drilling holes and 
reamering. 

EXPERIENCED HANDS. 

With regard to the introduction of men 
experienced in aircraft work, this is, of 
course, a matter best left to the judgment 
of the management, but, if the manage- 
ment themselves have had no practical 
experience of aircraft work, then experi- 
enced men as instructors or inspectors 
must be introduced. It is not then in the 
interest of the management to interfere 
with them or criticise their methods, ex- 
cepting when they fail to produce finished 
work. 

If you do honestly see ridiculous 
systems or methods employed by these 
men, then you can say to yourself that 

27 



HOW AN AEROPLANE IS BUILT 
you have also failed ; that is, by selecting 
the wrong men. These remarks can well 
receive the consideration of the manage- 
ment of some few works, and be taken to 
! heart by them. In other words, " Don't 
[ interfere with things you know nothing 
about. Leave them to the specialist." 

Have you not scoured the advertise- 
ments in The Aeroplane for weeks to find 
this " specialist," has he not undergone 
an inquisitorial examination before your 
board of directors, and has he not been 
told that his services will be accepted on 
account of his previous experience, and 
on condition that if he fails, penalties 
almost equal to those of the Spanish 
Inquisition will be inflicted on him? 

PROPORTION OF WORKERS. 
The proportion of metal and wood 
workers to erectors and coverers is one 
that requires thought and judgment and 
a keen grasp of the rate of production, 
for money and temper will inevitably be 
lost if this important matter is not properly 
dealt with. Remember that wood work 
is produced at double the rate of metal 
parts for the same number of hands. 

THE INSPECTION DEPARTMENT. 
The firm's own inspection department 
is a department that should be organised 
at once, as it may be regarded as a safety 
28 



HOW AN AEROPLANE IS BUILT 
belt for the firm, to prevent it from 
dropping into the sea of disapproval of the 
A.I.D. 

A well-lighted quiet room, with a well- 
finished bench and lock-up drawers, a vice 
and a few stools, are required, with a nest 
of bins and drawers capable of holding 
copies of all the drawings which are issued 
to the works. These should be filed in 
batches, each batch constituting all the 
drawings of a complete component part, 
such as a rudder, or a fin. A separate 
drawer or drawers should be kept for each 
contract. Don't mix them all up, it wastes 
too much time. 

The inspectors should be chosen because 
they know their trade. We will take first 
the inspector of wood parts. He must be 
a skilled wood-worker, used to high-class 
accurate finish. If you can get him, have 
one who has been used to pianoforte 
manufacture. Next ascertain if he is a 
keen judge of timber and knows what con- 
stitutes sap and decay, or dead wood, and 
find out what he would do with a pocket 
of resin. Would he pass it, or not? 

He must also be well used to, or capable 
of, measuring up parts with dead accuracy, 
hundredths of an inch count, and so does 
shrinkage of newly worked timber. A 
A in. full is better than in, under 
size. Also, it may save your firm money 
if he remembers that ash is a hard wood, 

2<j 



HOW AN AEROPLANE IS BUILT 
but it shrinks. I once was told that it did 
not, but I don't believe so now. Also, a 
short cross-grain will not do for spars, 
inter-plane struts, and longerons, only long 
straight grain being suitable. 

Ask him how he would test a finished 
wing spar without damaging it? There is 
one very simple way that works all right ; 
take it up with both hands, hold it level 
with your chest, and shake it vigorously. 

He should also have a knowledge of the 
various makes of glues, and how to pre- 
pare them for use. Certain glues now in 
use in aircraft work require careful treat- 
ment and must not be over-heated. If 
they are, they will be spoilt, and bad joints 
will result. Also glue must be made fresh 
each day, and the glue pots cleaned out 
thoroughly. 

The inspector of metal work may now 
be considered. He must be an all-round 
first-class mechanic, and preferably have 
had experience in both machining and 
fitting. He should also be thoroughly 
accustomed to the use of a micrometer, 
gauging, accurate setting up and marking 
off, and he should appreciate what it is to 
have to work to a five-thousandth of an 
inch. 

THE INSPECTORS' POSITION AND 
EQUIPMENT. 
The importance of the posts held by the 
firm's inspectors should be recognised by 

30 



HOW AN AEROPLANE IS BUILT 
the firm for whose reputation and interests 
they are working, and the inspectors' 
reports should receive the careful con- 
sideration and attention from the general 
manager and works manager that they 
deserve. Also the inspectors themselves 
should realise and appreciate the position 
they hold, and act accordingly. 

The firm should supply the inspectors 
with a reasonable kit of tools to enable 
them to measure accurately the com- 
ponent parts, and experience has shown 
that the following may be considered a 
useful selection. For our purpose, we will 
take up either a Brown and Sharpe or 
Starretts' catalogue of small tools. In this 
case a Brown and Sharpe small tool 
catalogue, No. 25A, is to hand. From 
this the following tools may, with advan- 
tage, be ordered: — Micrometer calliper, 
No. 2, English measurement, — \ in., 
with rachet stop, for strainer work ; micro- 
meter calliper, No. 10, English measure- 
ment, — 1 in., with rachet stop; micro- 
meter calliper, No. 30, English measure- 
ment, — 2 in., with rachet stop; micro- 
meter calliper, No. 235, rolling mill 
gauge, English measurement, — 0.400 
in., with rachet stop; inside micrometer 
calliper, No. 250, 0.200—1 in., English 
measurement ; inside micrometer calliper, 
No. 252, \ in. — 1\ in., English measure- 
ment ; B. and S. combination square, with- 



HOW AN AEROPLAN E IS BUILT 
out centre head, No. 401, size 6 in. ; B. 
and S. protractor, with reversible pro- 
tractor head, size 18in., English measure- 
ment ; improved bevel protractor, No. 
493, 12 in. blade ; vernier calliper, No. 
570, English measurement, size 6 in. 

THE INSPECTOR'S DUTIES. 

The general duties of the Inspection 
Department are to inspect and pass all raw 
material ; to see that none but passed 
materials are issued to the works ; to look 
for and investigate and report on all 
unsatisfactory material, and stop further 
use at any stage of its conversion into 
finished parts ; to inspect all parts when 
finished, before they are passed to the 
A.I.D. for inspection; to watch the 
assembly of all such component parts as 
fins, rudders, tail planes, elevators, and 
fuselages, and see that no parts are used 
that are not passed by the A.I.D. ; and to 
see that all rejected parts made by outside 
firms are returned to stores with a label 
attached, stating the name of the maker 
and the precise cause for rejection, so 
that the firm concerned may know the 
cause for rejection. 

A list should be sent each day to the 
works manager containing : — 

(1) Lists of parts rejected due to faulty 
workmanship, and being under size, with 
name of workman and department. 
32 



HOW AN AEROPLANE IS BUILT 



(2) Parts rejected due to faulty material, 
with maker's name. 

(3) Parts rejected due to drawing altera- 
tions and modifications. 

(4) Lists of parts or material required to 
be replaced, owing to being scrapped. 

PLANNING DUTIES. 
The duties of the Planning Department 
may next be considered. It may be 
briefly said that it is their job to ascertain 
the best way to do a job and to detail 
the operations. For this purpose an instruc- 
tion-sheet should be issued to the works 
with each order and drawing, and it should 
not be left for the workman to find out. 
Thus, work should not go to the fitting shop 
first, when it should go to the machine 
shop . 

They will also keep records of material 
in store, and order all special material that 
is required and specified when looking 
through the drawings. They will also 
issue the drawings in the rotation in which 
the parts will be required in the erecting 
shops. This will save the erecting shop 
from getting the last thing first and the first 
thing last. 

THE PROGRESS DEPARTMENT. 
The Progress Department will receive 
these orders and see that the parts are 
produced in proper rotation in quantities 

C 



HOW AN AEROPLANE IS BUILT 



as required. They will keep track of all 
orders in the shop ; record daily progress, 
and report each day to the Works 
Manager any parts that are getting behind. 

Orders for work requiring special pre- 
cedence over other work will be dealt 
with on special orders, which have some 
identifying mark or colour, to distinguish 
them from the ordinary work. 

FINISHED PARTS. 
The Finished Part Stores should be 
separate from all other stores, and should 
preferably be near the Inspection Depart- 
ment. From here all parts required by 
the erectors should be issued, and from 
no other stores. This is essential, as it 
prevents parts which have not been passed 
by the A.I.D. being issued to the erectors, 
which is of the greatest importance. 



34 



CHAPTER II 



GETTING TO WORK. 

Having dealt at considerable length with 
the outline of the organisation required in 
any works, in a more or less modified 
form, for producing aircraft parts, we will 
now assume that orders have been issued 
by the General Manager to the Works 
Manager to proceed with the immediate 
construction of ten tractor biplanes of any 
ordinary commercial type. 

For the sake of getting quick-finished 
production and deliveries the orders may 
be issued for two batches of five. The 
necessary orders having been issued to the 
Wood Machining Department for the 
wood to be cut and machined for five com- 
plete sets of wood components, the most 
suitable timber will be carefully inspected 
and selected from the pile. 

BEGINNING THE FUSELAGE. 

In this case we will assume that the 
fuselage is the unit selected for the start. 
The timber required in this case is spruce, 
about l\ in. square tapering down to 1 in. 
square to form the longerons, the length 
being about 19 ft. in two lengths. 

The spruce selected should preferably 

35 



HOW AN AEROPLANE IS BUILT 



have a fine grain, which, when the 
longeron is in its permanent position, 
should form vertical lamina?, as it develops 
the greatest strength in this position, and 
also adapts itself to the curves or bends 
required in forming the streamline contour 
of the fuselage. The wood might also be 
selected for its cream-like colour, as this 
coloured wood is generally found to have 
the qualities required. 

SAWING UP. 
Having chosen a 3 in. plank with 
a fine grain of horizontal or vertical 
laminee, not less than eight in number, if 
possible, the plank can be taken to the 
circular saw and cut into Its in. battens 
by 3 in. These will be laid on their 3 in. 
face, and again cut down the middle into 
the approximate section or size required, 
namely, in this case, 1 rein, by Ire- in. 
Cut this way, it will enable the " rift 
sawn," or vertical, grain (see Fig. 1) to 




Rl FT SAWN TIMBER 

Fig. 1. 

36 



HOW AN AEROPLANE IS BUILT 
be obtained as required. To make the 
whole operation clearer the sketches may- 
be referred to. (See Fig. 2.) 




cutting longerons 
Fig. 2. 

The timber having been rough-sawn to 
size, it may be as well for the Works 
Inspector to see it before further work is 
done to it, and satisfy himself about the 
quality. Assuming this to be satisfactory, 
it then may be passed on to the planing 
machine and have its sides squared to 
lirkin., which will be the margin required 
for shrinkage. 

A LONGERON JIG. 
If the foreman of the wood machinists 5 
shop is a quick energetic man, he 
will now make a simple jig (see Fig. 3) 
for tapering these battens from ls 9 2 in. 
at one end to 1 # 2 - in. at the other 
end, in the following manner: — Get a 
piece of hard wood, about 20 ft. by 6 in. 
by \ in. The top and bottom surfaces and 

37 



HOW AN AEROPLANE IS BUILT 
one edge of this must be planed true. 
Next, place the longeron on this hard 
wood batten and equalise its position on 
the batten at either end. After having cut 
the longeron about l\ in. longer than its 




tapering- ' Longerons 
Fig. 3. 

correct length, one end should be clamped 
down at \ in. from the straight edge of 
the batten and the other end flush with 
the edge. Test the straightness of the 

38 



HOW AN AEROPLANE IS BUILT 
longeron and fix it with a few additional 
clamps. Having assured yourself that the 
longeron has no curves in it, get another 
piece of hard wood the same length as the 
longeron, and perfectly true, about 1 in. 
by 2 in. section, and lay it along the back 
of the clamped longeron. Then glue and 
screw it to the hard wood batten and place 
a cross stop at each end to keep the 
longeron correctly in its bed in the jig. 
This jig will then hold the longeron in 
position when being machined. 

Whilst the longeron is being passed 
across the French vertical spindle, the 
cutter of which is adjusted to project 
exactly \ in., it follows, therefore, that if 
the edge of the hard wood batten is 
pressed against the spindle underneath the 
cutter, commencing at the end where the 
longeron is \ in. from the edge, no cutting 
of the longeron will take place, but as it is 
slowly pushed past the cutter, the cutter 
will begin to remove the required amount, 
continuing to do so until the end of the 
longeron is reached, which is what is 
wanted, and the maximum J in. at the end 
is removed. 

When the longeron is now measured it 
will be found to be 1A in. at one 
end, tapering to 1^ in. at the other 
end, which is exactly what is required. 
Repeat the whole operation on one more 
side and the longeron will be found to be 

39 



HOW AN AEROPLANE IS BUILT 
the correct finished taper, namely, taper- 
ing from 1A in. square down to lm 
in. square. This work can also be done 
on the planing machine in a horizontal jig. 

The longerons can all be worked this 
way and passed to the inspection depart- 
ment as completed, to be inspected, 
passed, and stamped ready for issue to the 
erecting shop, where the longeron will 
have to be cut in two as the fuselage is 
built in halves. 

It may be advisable for the above 
longerons to be machined in two separate 
lengths. 

FUSELAGE STRUTS. 

The next component parts to be con- 
sidered will be the struts for the fuselage. 
In accordance with modern practise and 
design, which we can assume has been 
adopted, they will be square section, 
tapering from about 1 in. each side of the 
centre of the length to the ends on all four 
sides, and fluted on two sides. 

For our purpose we will assume that the 
lengths vary between 3 ft. and 1 ft. 3 in., 
and that the centre section is 1| in. square, 
diminishing as the rear end of the fuselage 
is reached to % in. square, all tapering at 
the ends to f in. square, where they bed 
and fit into the steel fittings on the 
longerons. 

The timber for the struts may be cut 

40 



HOW AN AEROPLANE IS BUILT 
from any straight grain plank, care being 
taken to select as far as possible a good 
fine grain for the long struts. The plank 
being taken to the circular saw, the 
required number of pieces of each size are 
cut, each about -J in. larger in section than 
the finished size to allow for planing up to 
ik in. above size. 

These lengths of timber can now be cut 
about 1 in. longer than the finished length 
and sent to the setter-out, who will, before 
working on them, submit them for inspec- 
tion. After they have been passed for 
quality, the setter-out will find the centre 
of each and mark off 1 in. each side of the 
centre of the length. This is where the 
lightening begins, the lightening being 
t 5 6 in. deep and f in. wide, finishing 
about \\ in. from each end of the correct 
length. 

This having been done, they will be 
taken back to the wood machining depart- 
ment to have the four lightenings (two on 
each of the two opposite sides) cut out on 
the spindle. 

A STRUT JIG. 

The first strut having been completed, it 
will be at once sent off to the wooden jig 
maker, who, after carefully consulting the 
drawing, will at once proceed to make the 
jig (see Fig. 4) for holding them whilst they 
are tapered on the vertical spindle. 

4' 



HOW AN AEROPLANE IS BUILT 
This jig will consist of a hard piece of 
wood about 6 in. longer than the strut, 4 in. 
wide by f in. thick. The centre of this 
will be carefully squared off, and 1 in. one 
side of this marked, corresponding to the 
beginning of the lightenings each side of 
the centre portion of the strut. Next, lay 
the strut on the board, with the centre 
of the strut corresponding to the centre of 




Fig. 4. 



length marked on the jig board. Set strut 
back J in. from the edge where the 
lightening begins, and is in. from the 
edge where the correct end of the strut 
occurs. Clamp the strut firmly in this 
position, and then fix another piece of hard 
wood on the inside of the strut, glueing 
and screwing it to the 4in. by f in. jig 
42 



HOW AN AEROPLANE IS BUILT 



board. Cut off the ends true and fix a 
cross strip across the board with a screw 
projecting through it horizontally, with the 
point filed up to a sharp chisel edge. This 
is for the purpose of gripping the strut in 
the jig. 

TAPERING A STRUT. 

The jig now being ready for operation, 
it can be given to the spindle hand. 
He will take a strut, lay it on the jig, press 
it against the longitudinal strip, and force 
the end on to the chisel-pointed screw (see 
Fig. 4), the cutter in the spindle being 
about 1J in. wide, projecting \ in. On 
pushing the jig board past the cutter, 
pressing the jig board against the spindle, 
the cutter will remove the first side of the 
taper. This being done, remove the strut, 
and lay against the longitudinal fixed strip 
a tapered strip of hard wood packing, cor- 
responding in size to the quantity of wood 
previously removed by the cutter. This 
will pack out the strut and enable the 
cutter to remove the portion on the 
opposite side. 

Two opposite sides are now completed, 
and all that it is necessary to do is to repeat 
these operations on the remaining sides at 
each end and the strut will be finished, all 
except cutting to the dead length. 

The above mentioned operations refer 
to all struts, the only other difference being 

43 



HOW AN AEROPLANE IS BUILT 
that jig boards will be required for each 
strut of a different length, as the taper 
varies slightly. This work can also be 
done on a jig board, which holds four 
struts on the planing and thicknessing 
machine. 

FRONT END STRUTS. 

At the front end of the fuselage we will 
assume that four ash struts are required, 
two each side, for stiffening the fuselage 
and attaching the engine plate. These 
will be flush on the inside and sunk and 
lightened on the outside, right and left- 
handed. As these struts have to bear con- 
siderable strain and vibration, quality of 
timber and fine straight grain is again 
essential. The front struts will be about 
2 ft. 5J in. long, 5 in. wide and 1J in. thick, 
with the ends tapered down, on one edge 
only, to 3 J in. 

^ Commencing at 7 in. from each end, the 
" sinking," or lightening is commenced at 
7f in. on either side of the centre of length 
and is carried towards each end of the 
strut, diminishing in width as the end is 
approached, the lightening stopping at 
2\ in. from the end (see Fig. 5) with a 
margin or flange at the sides | in. thick. 

Before cutting up an ash plank it will be 
best to get the wood setter-out to mark off 
the outline of the strut on a mahogany 
board, taking care to leave an excess of at 

44 



HOW AN AEROPLANE IS BUILT 
least f in. on all sides of the outline to allow 
for shrinkage and cleaning up. 




ASH FUSELAGE STRUTS 
Fig. 5. 

The template having been cut out and 
completed and checked by the inspection 

45 



HOW AN AEROPLANE IS BUILT 
department, with the drawing, it will be 
sent to the wood marker -off, who will go 
to the machining shop and mark off the 
outline on the selected ash plank, which 
can then be taken to the band saw. These 
ash struts may then be cut out, after which 
they can be sent to the wood-finishers' 
benches to be finished and then passed on 
to the marker-off to set out the lightenings, 
which will be done on the spindle, in two 
cuts. 
*€ 

CROSS STRUTS AND FUSELAGE SPARS. 

We can assume that the cross struts for 
the front part of the fuselage consist of 
1| in. square spruce, which must again be 
of exceptionally good quality, and long, 
fine grain. This must be cut from a 
selected plank and put through the thick- 
nessing machine, after which it can be sent 
to the wood-finishers' benches to be cut up 
into the correct lengths, plus \ in. to allow 
the erectors to fit and bed the ends to the 
top longeron and the front bottom fuselage 
spars which form the bottom longitudinal 
members of the fuselage. 

These will be of ash, about 6 in. deep by 
1^ in. thick, and, say, 6 ft. 6 in. long, 
tapering down to 1^ in. square at the rear 
end, with three lightenings in the centre, 
each side (see Fig. 6). 

A template of this should next be made, 
not forgetting the \ in. full over finished 

46 



HOW AN AEROPLANE IS BUILT 
dimensions to allow for shrinkage and 
cleaning up to A in. full. The template 
being made, the marker-off will mark off 
the outline on the ash planks. These can 
then also be sent to the band saw and then 
sent to the wood-finishers' benches. The 
ash struts and the front bottom fuselage- 
spars can all now be taken to the marker- 
off, who will outline the lightenings in 
pencil, and then they will be sent to the 
wood machining department to have the 
lightenings cut out on the French spindle, 
each lightening being done, half at a time, 
and reversed upside down to finish the 
uncompleted half. 




ASM FUSELAGE SPAR 

Fig. 6. 



We will assume the lightening is f in. 
deep each side, and the radius at the sides 
\ in. The spindle work being done, it 
may be necessary for them to be sent to 
the wood -finishers to have the lightenings 
cleaned out where the spindle did not 
reach, as is sometimes the case. After 
this has been done the whole lot can be 
sent to the inspection department to be 
passed and stamped. 

47 



HOW AN AEROPLANE IS BUILT 



THREE-PLY TIES. 

On the assumption that the design of the 
machine is fairly modern, and as adopted 
in a few cases, we will arrange for the front 
part of the fuselage to be tied together with 
I- in. three-ply, with lightening holes cut 
out in accordance with the plan. These 
will be set out on one sheet of three-ply, 
which should be large enough for this 
purpose, to avoid joints, which would 
constitute a grave weakness. 

The first sheet having been outlined and 
this passed, it can be laid on ten other 
sheets and the lot fastened together with 
fine wire nails, which should be plentiful, 
and placed principally on the part of the 
three-ply to be cut out, about 2 in. pitch. 

If this is not done, damage may be done 
to the edges of the three-ply by the jigsaw. 
After this is done the sheets of three-ply 
will be taken to a drilling machine, and 
1 in. to H m - holes should be drilled in 
each lightening to be cut out, to enable the 
jigsaw operator to pass the jigsaw blade 
through. 

When all the lightenings have been cut 
out, the sheets can be sent to the wood- 
finishers' benches to be cleaned up, ready 
for passing by the inspection department, 
and put in the finished part wood stores 
ready for issue to the erecting shop. 

The next part to be provided will be the 
4 s' 



HOW AN AEROPLANE IS BUILT 
ash distance pieces for the rear portion of 
the fuselage in line with the front spar of 
the tailplane, these will be of ash and be 
about 1 ft. 3 in. long by 5 in. wide by 1 in. 
thick, lightened out, this work being done 
in a similar manner to the front ash struts. 

The three-ply covering at the top and 
bottom and sides of the fuselage for 
strengthening and tying the rear end of the 
fuselage together can be now cut out in the 
same manner as described for the front 
ends. 

THE STERN POST. 

The ash stern post can now be put in 
hand. This will have to be of exception- 
ally good material, to avoid being rejected. 
It may be assumed that it is about 1 ft. 8 in. 
long by 4J in. by 1| in., with bevelled 
edges, to suit the contour of the sides of 
the fuselage, this will preferably be cut out 
of a rift-sawn plank (see Fig. 1), as the 
grain in this case will afford the most 
suitable strength. 

The upper portion of the post being cut 
away each side on the band saw, and 
finished on the bench, the bevel can be 
done on the planing machine or on the 
French spindle. 

UNDER-CARRIAGE STRUTS. 
The struts for the landing chassis can 
now be put in hand, these must be made 
from spruce of clean straight grain, which 

49 

D 



HOW AN AEROPLANE IS BUILT 
is the extent of the specification for struts 
for this purpose, of course free from resin 
and any shakes, the length being 4 ft. 2 in. 
by 1\ in. by 2 in. streamline section with 
ends cut and bevelled on two angles to 
support the fuselage, and the other or 
lower end to be fitted into the sheet steel 
fitting. 

The timber having been selected and the 
template of the outline having been cut out 
i in. full, the outline can be marked out 
off the template onto the spruce plank, 
which has been cut down from a larger and 
thicker plank, and planed up both sides to 
2 J in. thickness. It is then taken to the 




STRUT 

BOX jlG FOR SPIINDLING STRUTS 



Fig. 7. 

band saw and cut out to the outline, 
leaving each end 3 in. long, after which 
it is necessary to finish it up to the 
approximately finished streamlined section 
and dimensions, which can be done on the 
spindle, in a semi-box jig which covers the 
strut to be spindled, but which supports it 
and holds it in position (see Fig. 7), the 
edge of the jig which presses against the 
spindle being curved or contoured accord- 
ing to the design of the strut. 

50 



HOW AN AEROPLANE IS BUILT 



A BOX JIG. 

The jig will consist of a board about 5 ft. 
long 9 in. wide by 1 in. thick. At a 
distance apart of 4 ft. 8 in., securely fix 
two stout cross - battens about 9 in. 
by 3 in. by 2 in. to the board, on 
the top of these cross-battens, glue 
and screw a piece of hard wood 
9 in. by 4 in. by J in. so as to form a 
rabbet of the cross-battens, and along one 
edge of the board on the same side as the 
cross-battens glue and screw a longitudinal 
batten or strip 1^ in. wide and 2 in. thick. 

Into this space the strut is placed and 
the cutter of the spindle having been 
accurately ground up to a contour of a 
quarter of the whole streamline, all that 
has to be done is to pass the jig containing 
the strut in its unformed state past the 
cutter on the spindle. A quarter of the 
strut is now practically formed accurately ; 
the next thing for the spindle hand to do 
now is to slide the strut out and do the 
opposite side in a similar manner. One 
half of the strut is now complete, namely, 
the side next to the table of the spindle. 
Take out the strut, reverse its position in 
the jig and replace the cutter for the one 
for the rear side, and repeat the two 
previous operations, and the machining is 
complete, it can now be sent to the 
wood-finishers' benches to have the ends 

5* 



HOW AN AEROPLANE IS BUILT 
trimmed, and to be cut nearly to the 
required length. 

ASSEMBLING AND ERECTING. 
The erection of the rear half of the 
fuselage can now be commenced, and, for 
the purpose of this article, we can assume 
that the fittings have been made, and that 
the swaged tie-rods, fork-ends, and nuts 
are in stores, also all necessary bolts and 
nuts. 

Owing to the design of the fuselage, the 
best way will be to assemble the bottom 
part of the fuselage first in a jig. To do 
this, it must be built upside down, to 
permit of the three-ply being glued and 
screwed down on the bottom side at the 
rear end. 

A jig being a mechanical apparatus for 
enabling labour to produce interchange- 
able component and whole parts, it follows 
that as much care and thought, and some- 
times expenditure of time and material, 
must be spent on it, as the cost of 
producing perhaps two or three of the re- 
quired component parts by other methods, 
which invariably fail in producing re- 
petition work accurately. To start with, 
ordinary wooden setting-out tables are 
useless, for however tightly the boards are 
clamped together, and cross-battened 
underneath, expansion and contraction 
always takes place ; therefore, until a 
52 



HOW AN AEROPLANE IS BUILT 
better method is generally known, it is best 
to cover the top, on which the setting out 
is done, with three-ply about if in. thick, 
as the contraction and expansion of this 
material is negligible, and" upon this jig 
work can be developed and built up. 

AN ASSEMBLING TABLE. 

Therefore, we can proceed to build the 
table of | in. or 1 in. "flooring," well 
clamped together and screwed to cross 
battens with about 3 ft. centres, of the same 
material. It should then be put into the 
shop, where it is to remain permanently, 
carefully laid and bedded horizontally on 
about four trestles, as the length will be 
about 12 ft. 6 in. long by 4 ft. 

There it should, if time permits, be 
allowed to remain for two or three days to 
season, after which the top should be care- 
fully tried for level with a straight-edge, 
in the following manner. Try each side 
and each end, and try it square across the 
centre, then diagonally from corner to 
corner, and make it true to all these tests. 

It may then be covered with the three- 
ply, which should only be screwed down 
with just a sufficient number of screws to 
hold it evenly and firmly down to the table. 
Do not attempt to plane the top surface if 
uneven. Three-ply, t% in. thick, won't 
stand this. Take it up and alter the deal 
boards below. 

53 



HOW AN AEROPLANE IS BUILT 
Having prepared and finished the table, 
plane one edge of it carefully, and test it 
with a straight-edge until it is true. This 
edge is wanted by the setter-out from which 
to use his square, and as a base-line. Also, 
don't trust to squares ; only about one in 
ten is dead true. After you have set out 
a line at right angles to a base-line, test it. 
This can be done by the following method, 
which most men know. 

Measure off on the base-line any four 
units of length, and three of the same units 
on the line to be checked, the third side 
or hypothenuse of the triangle should 
equal in length five units. This is known 
as the 3—4 — 5 — method, and these units 
may be inches, feet, yards or miles. The 
method is based on the old 47th Prop, of 
the First Book of Euclid, which proves 
that the sum of the squares of two sides of 
a right-angled triangle are equal to the 
square of the hypotenuse, or side facing 
the right angle. Thus 3 J + 4 s = 5\ or 
9 + 16 = 25, so the angle between 3 and 4 
must be a right angle. 

Check these distances with the use of 
fine trammel points if possible. If this last 
measure does not meet the extreme points 
of the other measurements exactly, then 
the line which is supposed to be at right 
angles to the base-line is incorrect, and a 
further check must be made. 



54 



HOW AN AEROPLANE IS BUILT 



SETTING OUT. 
We can now proceed to study the plan 
of the fuselage, preparatory to setting it 
out on the jig table. Having done this, the 
first thing to do will be to find accurately 
the centre of the table. Mark these points 
with a soft pencil, then check each of these 
points from the base-line, or trued edge, 
of the table. If they are not dead ac- 
curate, alter the point so that each point 
is absolutely the dead same distance from 
the base-line as the other. This is most 
important, and if not given minute atten- 
tion, may cause endless trouble and 
perhaps cause the bottom part of the 
fuselage to be so out of square and in- 
accurate as to necessitate it being scrapped. 
It may only be J in. out, perhaps onlyiV 
in., but it is wrong, and, as wrong, it will 
be rejected. Excuses of any kind cannot, 
and will not, be tolerated. 

It is best, owing to the accuracy re- 
quired, for the setter-out to provide him- 
self with a pocket-knife with a conveniently 
shaped handle, and, after having found 
the points approximately with a pencil, 
to mark all measurements permanently 
with a fine knife cut, after he is satisfied 
they are correct. Pencil marking is useless 
for real accuracy, but must be used when 
setting out spars. 

Having found the centre of the table at 

55 



HOW AN AEROPLANE IS BUILT 
each end, lay a straight-edge along the 
table and with the pocket-knife draw or 
cut in once only a fine centre line. You 
can then go over this with a pencil to make 
it more clear. Next, set out the position of 
the true ends of the longerons, where they 
join up to the front half of the fuselage, 
then put a line square across the table 
about 4 in. from one end. This will enable 
the longerons to be accurately placed in 
position when the time comes. 

It will be well to pencil on this line, for 
the general information of all concerned, 
what it is for, to prevent mistakes. From 
this point, the distance to the centre line 
of each cross strut should next be marked, 
and when these are all done, put a square 
line across, cutting each point. 

Next refer to the plan, and from that 
obtain the cross widths between the 
longerons at each cross strut. Carefully 
put a cut line at each end, this will enable 
you to set the longeron out accurately in 
plan on the table, and get the correct con- 
tour. (See Fig. 8.) 

LAYING ON. 
Having done this, lay on one longeron 
and clamp it to these marks ; then the 
second ; after which take a steel tape and 
accurately check all your distances in 
between the longerons at each strut, taking 
care to do this on the centre-line of each 

56 



HOW AN AEROPLANE 



IS BUILT 




57 



HOW AN AE RO PLA N E IS BUILT 
strut, and not at the side. The centre-line 
may with advantage be marked in fine 
pencil on the longeron (cutting with a pen- 
knife in this case is not permissible). 

Having adjusted any inaccuracies, small 
pieces of hard wood about 4 in. by 2 in. 
by 1 in. may be fixed down by means of 
glue and screws to the table, being gently 
pressed against the longeron until their 
position is definite, and the glue sufficiently 
set. When this has happened they can be 
further secured by means of a couple of 
screws. 

The position of these distance pieces 
from either side of the centre-line of the 
strut should be determined by the length 
of the steel fittings, and a small margin of, 
say \ in. each side allowed for freedom. 

Having fixed all these stops, hard wood 
turn-buttons should be fixed outside the 
longeron — (see Fig. 8)— to press it against 
the stops, when it is being finally fitted, not 
forgetting to use a piece of three-ply to 
prevent damage to the longeron. These 
turn-buttons are desirable on jigs, because 
they permit of quick release of longerons, 
struts, and other parts. 

STEAM BENDING. 

The bending of the longerons to fit the 
contour required by the jig will entail the 
use of a steam-bending plant, using low- 
pressure steam ; preferably about 10 lbs. 
per square inch. 

58 



HOW AN AEROPLANE IS BUILT 
The steam-box should be long enough 
to take the whole of the longeron, for it is 
necessary to steam the whole longeron 
before bending. Care should be taken that 
the grain lies vertically when the bend is 
completed. If this process is not carried 
out crushing of the fibres will occur, and 
the strength destroyed. 

The steam-bending plant must be close 
to the jig, for the value of steam-bending 
will be lost if the longeron is allowed to get 
cold on being taken out of the steam-box 
before it is put into the jig. The transfer- 
ence from steam-box to jig should be made 
as quickly as possible, and the longeron 
should be allowed to cool in position for 
a few hours. 

FITTING UP. 

Having got the longerons laid out on the 
jig table accurately in position, and all 
measurements carefully checked, the next 
thing to do will be to fit the steel fittings 
on to the struts, taking care in doing so 
that an equal amount is cut off each end 
of the strut, measured from the centre, 
especial care being taken to see that the 
strut beds accurately and squarely into the 
fitting. When this has been done the strut 
should be tested in between the limits of a 
" length jig " made up to represent a short 
length of fuselage — (see Fig. 9) — with a 
sliding adjustment, which can be locked to 

59 



HOW AN AEROPLANE IS BUILT 

any required measurement or angle within 
limits. 

A LENGTH JIG. 

This kind of jig will be found useful for 
checking many classes of work, and a few 
of varying lengths can be made with ad- 
vantage. They can, of course, be 
elaborated to suit special requirements. 

The strut and steel fittings having been 
tested for length and found correct, the 
strut should be tried in between the actual 
longerons for fit, and it should go in with 
a gentle pressure. When it is in its final 
correct position the bolt-holes in the fitting 
should be very carefully marked off on the 
longeron for drilling ; this can be done 
with advantage by using a piece of steel 
exactly fitting the bolt-hole, about 4 in. 
long, and slightly countersunk, like a rivet- 
snap, and giving the piece of steel a few 
light taps to mark the longeron. 

This having been done, pencil a distin- 
guishing mark on the strut and on the 
longeron, so that it will be picked out again 
and put into the same place in the same 
fuselage. Preferably use a rubber stamp. 

All struts will be fitted in this manner, 
and after this work is completed, each 
longeron should have the position of the 
fittings and the bolt-holes marked out for 
the vertical strut fittings, after which the 
longerons should be taken out of the jig 
and the bolt-holes drilled on a drilling 
60 



HOW AN AEROPLANE IS BUILT 




61 



HOW AN AEROPLANE IS BUILT 
machine with the aid of a metal plate jig 
clamped to the longeron to prevent the 
holes from being drilled out of centre. As 
no inaccuracies in bolt-holes in wood work 
are permissible, extra care must be taken 
with the drilling, and wood drills used, 
twist drills not being suitable. 

GETTING TOGETHER. 

All the various bolt-holes being drilled, 
the longerons will at once be returned to 
the erecting shop. Here the longerons, 
being of spruce, should be neatly bound 
with J-in. India tape, tightly laid on after 
the surface has been well covered with 
glue, and also the tape, each layer half 
overlapping the previous one and the end 
secured by a couple of f-in. by 20 gauge 
brass gimp pins, after which all surplus 
glue may be removed with a damp rag. 
This binding is only required where the 
steel fittings are placed, and should extend 
about J in. either side. 

The longeron will then be replaced in 
the jig and the final assembly of the rear 
bottom part of the fuselage will be com- 
menced. It will be best to put in the 
shortest struts first and work forward, as 
this method will secure the ends of the 
longerons having the sharp curves fixed 
first, and also it will enable another couple 
of erectors to fit, glue, and screw down 
the three-ply at the rear end. 

62 



HOW AN AEROPLANE IS BUILT 



SIMPLE HINTS. 
In bolting the fittings on, it is usual in 
seaplane work to give the bolts a coat of 
enamel, and tap them home, to dry in 
position, as the corrosion by salt water on 
steel fittings is very severe indeed. This 
helps to increase their life, and might as 
well be done in all aeroplanes. In tighten- 
ing up bolts, it is well for erectors and 
others concerned to bear in mind that the 
size of the bolts they are handling are any- 
thing between £ in. to A in. B.A. 
threads and \ in. and f in. B.S.F. 
threads, therefore it is not necessary to 
use a yard of 2-in. gas piping on the end of 
the spanner as a lever or to send for the 
" heavy gang " or millwrights, with 14 lb. 
slogging hammers, to drive the bolts home 
or lock up the nuts, as such methods are 
likely to smash the bolt or crush the head 
or nut into the soft wood. They would 
also put unnecessary strain on the bolt, 
and such methods do not find favour with 
the A.I.D. Also, incidentally, it may 
cause a man the trouble of having to look 
for a fresh job, besides proving that he is 
a B.F. (which stands for blithering fathead, 
and several other things). 

Properly proportioned spanners and 
box spanners must be provided for the 
purpose. Tightening up of nuts with pliers 
and pincers damages the edges of the nuts 
6 3 



HOW AN AEROPLANE IS BUILT 
and generally spoils what might otherwise 
be good work. 

The nuts will next have to be made 
secure, and the method which now seems 
to be most universally adopted is to file the 
bolt down if necessary, until about l-16th 
full is left projecting beyond the nut, and 
then to rivet this carefully over, taking 
care to hold a suitable piece of iron or 
steel bar at the back of the head whilst it 
is done. This riveting can best be done 
with a small ball-headed hammer weighing 
about ^ lb. 

THE TOP HALF. 

Having now completed the bottom por- 
tion of the rear end of the fuselage, it is 
necessary to commence on the top portion, 
which, being similar to the bottom, can be 
built in a similar manner, with the differ- 
ence that as the lower portion is not 
parallel to the top longeron, the distances 
of the struts apart will be slightly longer 
in the low portion, and it will for this 
reason be necessary to refer to the plan 
and see if the existing jig can be utilised. 

Otherwise a new jig will have to be pre- 
pared on similar lines. 

Assuming that the top and bottom por- 
tions of the rear end of the fuselage have 
been built, the next question to consider 
is, how is the fuselage .to be completed, 
with its side struts to put in, and all the 
swaged wires to be fixed and adjusted? 
6 4 



CHAPTER III 



ERECTING THE FUSELAGE. 

To enable this to be done easily it will be 
advisable to consider making a simple jig, 
which will ease the erection tremendously, 
and enable the work to proceed rapidly, 
and tend to prevent mistakes. For this 
purpose, make six portable columns stand- 
ing on feet, with adjustable top and bottom 
cross rails and longitudinals (see Figs. 10 
and 11). The use of this jig will enable 
work to be put in hand quickly, and when 
completed taken down. Reference to Fig 
10 will give an idea of this construction. 

Having completed the jig, the first thing 
to do will be to take the top rear portion of 
the fuselage and attach it to the top portion 
of the jig on the underside of the cross 
bearers as shown, and then put the bottom 
portion of the fuselage on the top of the 
lower cross bearers as shown. After which, 
level up the top portion of the jig with a 
spirit level, and then adjust the lower por- 
tion to the inclination given by the mea- 
surements of the lengths of the struts be- 
tween the longerons. 

After this is done and carefully checked, 
the struts with their fittings on them may 
be put in their respective positions and 
65 

E 



HOW AN AEROPLANE IS BUILT 




HOW AN AEROPLANE IS BUILT 
bolted to the longerons and riveted up, 
and the ash skid post fixed. Then the 
only work remaining to be done is to put 



plan 




floor 



FRQINT PORTION OF FUSELAGE JIG 

Fig. 11. 



67 



HOW AN AEROPLANE IS BUILT 
in the tie rods and fork ends with lock nuts, 
and to adjust the tension on them. 

Then the lower longitudinal and cross 
bearers can be lowered slightly, and any 
adjustment necessary in the tie rods will 
be at once seen while the rear portion of 
the fuselage is in suspension and the " line 
of flight " of the machine is in a true and 
horizontal position. In this manner the 
necessary trueing up for the fuselage can be 
done. 

THE FRONT SECTION. 

The front portions of the fuselage can 
now be constructed. They will have to be 
constructed in a jig similar in design to 
the rear portions, only these parts will be 
left- and right-handed, instead of top and 
bottom. Extreme accuracy will be neces- 
sary in all measurements, especially in the 
distance between the top longerons and 
the bottom ash spars, otherwise it will be 
impossible to join these front portions, 
when made, to the rear portions already 
finished, as the joint of the longerons is a 
plain butt-joint, with cover-plates of steel 
top and bottom, like fish-plates. 

A jig will have to be made for the left 
hand and also the right hand, as the out- 
sides are covered with three-ply wood, on 
one side only, namely, the outside, being 
attached to the longeron, engine bearers, 
cross bracing (which is of wood), and ash 
spars with small screws. 

68 



HOW AN AEROPLANE IS BUILT 

Assuming that the front portions of the 
fuselage are completed, and passed by the 
A.LD. Inspector, they will be taken to 
the erecting shop. To put them in the jig, 
the bottom stop and the longitudinal sides 
of the jig may have to be lowered slightly 
to enable them to slide into the slots made 
to hold them in the cross bearers. After 
they are in position, the tapered wedges 
will be driven home. This will clamp them 
firmly to the bottom cross bearers (see Fig. 
10), other adjustments being made that 
are necessary. 

CHECKING FOR ALIGNMENT. 

These having been completed, it will be 
necessary to try the whole jig with a spirit 
level, and some 22 gauge steel wire 
stretched along the top and bottom cen- 
tres, between the longerons, from end to 
end. Test them both, for vertical align- 
ment, about every 2 ft., by means of a 
plumb-bob line, from the top wire to the 
bottom wire, taking extreme care to see 
that the plumb line from the top wire 
touches the bottom wire at each point tried 
on the same side. This should be done in 
the presence of the foreman erector, unless 
two skilled mechanics are available. 

This check will be of the utmost value, 
as it will immediately show up any twist 
or inaccuracy in the fuselage, which must 
at once be rectified, either by alteration 
69 



HOW AN AEROPLANE IS BUILT 



of the jig, or alteration of the tie rods, or 
both, as may be necessary. If the greatest 
possible attention is not paid to this work, 
the fuselage will be all of a twist, which 
will not do, as it will seriously affect the 
machine when in flight, as the tail plane 
will be out of the horizontal with the wings, 
and the fin and rudder will not be vertical, 
therefore the importance cannot be over- 
estimated. 

BOLTING UP. 

Having checked the fuselage, both rear 
and front portions, and found them cor- 
rect, and the joints of the top and bottom 
longerons in perfect alignment, without 
any artificial means being used, the fittings 
for the joints may be placed in position, 
and the bolt-holes carefully marked off. 
The holes can then be drilled by means of 
an electric drill and jig, the greatest care 
and accuracy being required, to ensure the 
holes being drilled centrally and vertically 
through the longerons. 

These being done, the fittings can be 
bolted in position, thus permanently tying 
the front and rear portions together. 

THE NEXT STEP. 
If the works manager, or the foreman 
of the erecting shop, approves of the job 
as so far completed, the transoms, or cross 
ties, the seat bearers and the tank bearers, 
must now be fitted in. But if the fuselage 
70 



H OW AN AEROPLAN E IS BUILT 
is allowed to remain in the jig whilst this 
is done, it will delay progress with fuselage 
No. 2, and as this is not permissible, the 
fuselage must be very carefully removed 
from the jig and put on trestles which have 
been previously levelled up. 

In putting in the tank bearers and seat 
bearers, etc., the tops and bottoms of the 
front end of the fuselage must be accu- 
rately clamped together, before removal 
from the jig, with a distance piece in be- 
tween of the correct size to maintain the 
theoretical width, otherwise the tank and 
seat bearers will be incorrect. 

These having been fitted, the two com- 
pression struts, onto which the wing spars 
butt, must now be put in position, not for- 
getting when doing so that two fittings, left 
and right hand, have to be fitted onto the 
bottom ash spars at the same time, and the 
bolt-holes very carefully marked off, and 
drilled. After which, the fittings and struts 
may be put into position and bolted and 
riveted up. 

The flooring can now be fitted in. This 
will consist of f-in. spruce, suitably 
stiffened with longitudinal bearers, the 
flooring being put in across the machine 
and screwed down with brass screws. 

THE LANDING CARRIAGE. 
Having got so far, it will be as well to 
consider the landing chassis struts. These, 
71 



HOW AN AEROPLANE IS BUILT 
owing to their being splayed outwards, 
will have to have their ends cut to an 
angle, where they bed into the strut-fittings 
attached to the ash front spar. To carry 
out this work correctly a proper start must 
be made and the work carried out in a 
systematic and workmanlike manner. 

The first thing to do is to find out the 
distance from the top longeron to the floor 
of the shop and allow an extra half-inch 
for clearance when the wheels are on the 
axle. Having found the distance from the 
plan, which we. will assume to be about 
6 ft. 6 in., place the fuselage on trestles 
and packing. This height can be measured 
by placing a straightedge on the top 
longeron and measuring down to the floor, 
taking care before doing so to see that the 
fuselage is level longitudinally and trans- 
versely at each end and in the middle. 

Having done this, procure a straightedge 
about 7 to 8 ft. long, and lay it across the 
top of the fuselage on its edge, over the 
centre of the front chassis strut. After 
having marked the centre of length on it 
with a fine knife cut, and the extent of 
splay each side, which for our purpose we 
will call 6 ft. 9 in., which will be 3 ft. 4^ in. 
each side of the centre mark, attach a 
plumb-bob to each of these points. Allow 
the plumb-bob to hang down, and mark 
the point indicated by the point of the 
plumb-bob on a nicely planed board which 

72 



HOW AN AEROPLANE IS BUILT 
has been screwed to a couple of short 
trestles or supports, carefully made to 
coincide with the theoretical bottom of the 
wooden strut, and levelled up with a spirit 
level. 

Having done this, the erectors will have 
their top and bottom points to which to 
fit the strut, and this method will prevent 
any inaccuracy, as they can utilise the fixed 
bases in bevelling the strut ends time after 
time, thus enabling accurate results to be 
rapidly obtained. Having cut and fitted 
the top end of the front chassis struts to 
the top fittings, the struts can be taken 
out and the bottom junction fitting fitted, 
bevelled, and bolted onto the bottom of 
the front strut. 

REAR CHASSIS STRUTS. 

The next thing to do will be to fit the 
rear chassis struts, which are slightly more 
difficult, as they splay outwards and rake 
backwards and upwards. Thus there are 
two angles to contend with, and for this 
purpose the angle between the two struts 
should be carefully obtained from the 
drawing office if it is not clearly marked 
on the plan. 

The angle should be set out on a setting- 
out table, and a few stops screwed on to 
the table, to contain the chassis struts in 
their theoretical position whilst the rear 
strut is being shaped and fitted to the 



HOW AN AEROPLANE IS BUILT 
fitting. For this purpose the front strut 
should be clamped down on bearers, which 
are a sufficient height off the setting-out 
table to clear any projection of the junction 
fitting. This will enable the rear strut to 
be fitted up in an identical angle to fhe 
fitting which it will be in when permanently 
fitted and bolted to the fuselage. 

Having bevelled and fitted the rear strut, 
and having had it checked by the works 
inspector and the A.I.D., and stamped, 
the final assembly can be commenced. 
After the position of each chassis strut and 
the fittings on the bottom have been 
checked, the bolt holes can be drilled in 
position without further taking down. The 
bolts can be put in and tightened up and 
riveted over, thus finishing the fitting up of 
the chassis, with the exception of putting 
in the axle and attaching the wheels. 

The next thing to do will be to shape up 
the ash skid post, and fit the skid lever 
hinge fitting on, which, being more or less 
similar to bedding in the chassis strut fit- 
tings, will require no special remarks. This 
also applies to the four centre plane struts. 

STREAMLINE FAIRING. 
The streamline fairing on the top of the 
fuselage at the rear end, aft of the pilot's 
seat, can now be put in hand. This will 
consist of 3 6 -in. three-ply semi-circular 
uprights, the highest one being 9 in. high, 

74 



HOW AN AEROPLANE IS BUILT 
and the same width as the fuselage, notched 
out on the radius about 2-in. pitch with 
f in. by \ in. deep notches to take the f in. 
by \ in. spruce stringers which run longitu- 
dinally with the fuselage to support the 
fabric. There will be about 10 of these 
stringers and one extra heavy section on 
each side for attaching the whole of the 
fairing to the fuselage. The height of the 
semi-circular 3-ply uprights gradually 
diminishes towards the rear, until the tail 
plane leading edge is reached, where it 
dies out. The whole of the spruce stringers 
forming the skeleton framework of the fair- 
ing are covered with fabric, which will be 
doped when completed, and varnished. 

The covering on the top of the fuselage 
in front of the pilot's seat will consist of 
20-gauge aluminium sheet strengthened 
with ash bends underneath, attached to 
the fuselage and also to the aluminium 
sheet with brass screws. This will be dealt 
with later on when dealing with the manu- 
facture of metal fittings and work. 



CHAPTER IV 



WING STRUCTURE. 

Having dealt at some length with the 
construction of the fuselage and chassis, 
we may as well consider the construction 
of wings. As the machine is a biplane, 
there are two right-hand and two left-hand 
planes and one centre plane to make. For 
the purpose of maintaining continuous pro- 
gress in construction, we may as well com- 
mence with the centre plane, as this must 
be fitted up before the wings can be as- 
sembled on the machine. 

The first parts to produce will be the two 
compression struts which take the end 
thrust of the main upper wing or plane 
spars. These will be of carefully selected 
rift, or vertical grain, spruce of the best 
quality, the dimensions of each being about 
3 ft. 2 in. by 3^ in. by 2 in., lightened out 
on both sides on each side of the centre 
for about 8 in. This will leave the 
strut solid in the centre for about 
6 in., the lightening being f§ in. deep 
by 2f in. wide, the corners having 
about f in. radius to prevent splitting and 
fracturing. 

The most suitable timber having been 
selected, it will be taken to the circular 

7 6 



HOW AN AEROPLANE IS BUILT 
saw and cut down to 3 ft. 4 in. by 3f in. 
by 2i in. It is then advisable for the works 
inspector to see it. Assuming that he 
passes it, the next thing will be to put it 
through the planing machine, and reduce 
it to the correct size plus sir in. full over 
all to allow for shrinkage. It will then be 
sent to the wood setter-out, who will, after 
referring to the drawings, set out the four 
lightenings, which will have to be machined 
out on the spindle. 

If the spindle hand does the work care- 
fully and has his cutters properly sharp- 
ened, there will be no need to sandpaper 
out the lightenings when it comes from the 
spindle. This can be done, and is done in 
works where the spindle hand knows his 
job and is not driven at his work by some- 
one in authority whose sole aim in life is 
output from the department, regardless 
of finish. 

Such forcing the pace amounts to nothing 
less than scamping the work. It costs the 
firm pounds, and delays final production. 
To say the least, it should be severely dealt 
with, after a careful inquiry has been made 
of the spindle speed and the state of the 
cutters and the material they are made 
of. Also sandpapered work never has the 
same accuracy of finish as wholly machined 
work. 

Having received the compression struts 
from the spindle, the next thing to do is to 

77 



HOW AN AEROPLANE IS BUILT 
find the centre of the solid part between 
the lightenings and then mark off the ex- 
treme ends of the struts, not forgetting the 
fact that an additional amount must be left 
on the ends of the struts to enable the ends 
to be accurately cut to suit the dihedral 
angle of the wings. This angle is the up- 
ward slant of the wings towards the tips, 
and may be described as the angular space 
included between two planes which meet 
each other. 

FURTHER STEPS. 
Having completed the machining of .the 
struts, the wiring plates should be put in 
position, and the position of the bolts 
marked off. Then the holes should be 
drilled, so that when the compression ribs 
at each end and the intermediate ribs are 
in position, the wiring plates can be put on 
and bolted to the compression struts, and 
the swaged wires fixed, and the tension 
adjusted. 

However, before this can be done, the 
outside box ribs or compression ribs, and 
the three ordinary centre ribs, must be 
made. 

RIB MAKING. 
To make the ribs correctly to the con- 
tour and dimensions shown on the plan, 
it will be best to set out one on a thin hard 
wood board, and then cut and finish the 
board accurately to the shape of the rib. 
78 



HOW AN AEROPLANE IS BUILT 

After which this template can be used to 
set out the jig board on which the ribs will 
be constructed and checked and finished. 
Ribs will be described later on. 

To give an idea of the shape of the ribs 
which will be used in the construction of 
the wings and centre plane, we will assume 
that the length from the nose or leading 
edge to the trailing edge is 5 ft. 6 in. 
Therefore set out on the hard wood board, 
which will be the template of the rib, a 
straight line 5 ft. 6 in. long. This is called 
the chord line. The board should be not 
less than, say, 6 in. wide. 

SETTING OUT WING CURVES. 
The next thing to do is to produce the 
correct wing curves. On referring to the 
drawing we find that at about 6 in. from the 
left-hand end of the line a vertical offset 
of J in. is given ; therefore set up a fine 
line at right angles to the chord line across 
the board, and carefully cut in a mark J in. 
above the chord line. This represents the 
curved line or underside of the rib at this 
point. Above this dimension is another, 
which we will say is 3^ in., this represent- 
ing the top curved line of the rib, and as 
we refer to the drawing, we find that in 
this manner a number of points in the top 
and bottom curved lines of the rib are thus 
given on the drawing, thus enabling the 
rib to be set out. 



~9 



HOW AN AEROPLANE IS BUILT 
When all the points have been set out 
on the chord line and the vertical lines 
set up and the two points on each vertical 
line marked, all we have to do is to get 
two pieces of thin spruce about 6 ft. long 
by Jin. wide by A in., and tack them 
down to the board, so that one edge cuts all 
the points nearest the chord line, and the 
other the points at the top, farthest away 
from the chord line. The space enclosed 
thus is the true and required outline of the 
rib ; that is, if the given offsets are correct, 
which they are not always, in which case 
the mean average must be taken. 

Assuming that they are, and that the 
dimensions have been accurately set out, 
all we now have to do is to cut in a fine line 
with a knife, carefully following the curves 
of the laths nailed down, on the inside. 
The enclosed piece of hard wood will then 
be cut out on the band saw, and we must 
be careful to give instructions that all the 
points on the top and bottom curves are to 
be left in, so that they can be accurately 
worked down by the wood template maker. 
This gives the template maker sufficient 
latitude and material to ease off or soften 
any angular points in the curve which may 
arise. 

After the template has been made it 
should be sent to the inspection depart- 
ment and carefully checked and then sub- 
mitted to the A.LD. 

so 



HOW AN AEROPLANE IS BUILT 



RIBS. 

After it is passed and stamped it can be 
returned to the wood setter-out, who will 
mark off the spruce webs for the compres- 
sion ribs of the centre planes, which can 
then be tacked together, four at a time, 
and sent to the band saw, where they can 
be sawn out to within about in. of the 
line. It is necessary for this amount to be 
left on by the band saw, otherwise the 
spindle may not be able to finish them 
off clean. 

On coming from the band saw they will 
be tacked down to a template jig-board 
of hard wood, which is \ in. wider all 
round, to allow for the projection of the 
spindle-cutter, and sent to be spindled in 
a manner similar to the method adopted 
in spindling the fuselage struts. 

THE RIB JIG. 
After being spindled the webs will be 
sent into the wood parts department and 



JlG BOARD WEB REGiSTEl? 




Rl8 JIG 

Fig. 12. 

the jig-board obtained from the wood tem- 
plate maker (see Fig. 12). The jig-board 

Si 

F 



HOW AN AEROPLANE IS BUILT 
consists of a piece of hard wood such as 
beech, oak, or ash, about 1 in. thick, about 
9 in. wide, and 6 ft. long. On this will be 
laid a piece of selected board, planed both 
sides, and cut to the exact contour of the 
ribs less J in. on the top and bottom edges, 
the J in. being made up by the flanges on 
the top and bottom of the ribs. This 
board, or packing as it really is, will in this 
case be about If in. thick, as the web may 
be assumed to be about f in. thick, with 
lightening holes in the centre and ends. The 
flanges we may assume to be about If in. 
wide. The If in. packing will now be care- 
fully glued and screwed onto the centre 
of the 6 ft. by 9 in. board, and on the top of 
this two short pieces representing the sec- 
tion of the spars will be carefully and ac- 
curately fixed in position. These pieces 
of wood are for the purpose of accurately 
locating the position of the web on the jig 
and checking the holes, which are cut out 
to allow the spars to pass through. Having 
got so far, it will now be necessary to fix 
turn-buttons to the jig-board so that when 
the flange is bent to the curve of the rib, 
preparatory to being glued and screwed to 
the web, it may be accurately and per- 
manently retained in this position until the 
rib maker has had time to put in the screws. 

The next thing to do will be to cut 
two tb in. slots right through the If in. 
packing on the jig-board. These two slots 
82 



HOW AN AEROPLANE IS BUILT 
are the locating positions of the two small 
vertical stiffeners, to strengthen the web 
and prevent buckling under load. The 
slots take the vertical stiffeners and hold 
them in position whilst the rib is being con- 
structed. 

MAKING UP RIBS. 
The rib-jig having now been constructed, 
the best thing to do is to make up one or 
two sample ribs, which must be submitted 
to the inspection department, and if found 
correct sent to the A.I.D. for final inspec- 
tion and approval. After which the con- 
struction of the required number can be 
tackled. 

The method of procedure will be as fol- 
lows : — Take two rib-stiffeners and place 
them in the slots made for them in the 
packing-board of the jig. Then take a web 
and lay it over the spar sections to locate 
it. After having glued the edge of the web- 
stiffeners next the web, fix the screws into 
these. Then take the top flange and slip 
it in between the web-edge and the turn- 
buttons, carefully cover with glue the edge 
of the web, then press the flange up to it 
and fix in position by turning the turn- 
buttons. Then with a suitable sized brad- 
awl make the screw holes in the flange, 
about 4-in. pitch, and screw the screws in. 

SOME POINTS TO NOTE. 
Don't hammer screws in, as is done in 

S3 



HOW AN AEROPLANE IS BUILT 
many box and packing-case factories, for 
it is as well to remember that something is 
being made on which lives depend. 
Which, though it may not interest you, 
does interest the relatives of pilots. 

Also it is best to see that the screws are 
put in straight, and at right-angles to the 
flange through which they are passing, 
especially if the screw selected is only just 
long enough for its job. 

Also sharp screw-heads do not look nice 
when sticking up at all angles, and if you 
take the trouble to file them off, it, of 
course, weakens the heads, and possibly 
makes it impossible to remove the screw if 
it is at any time necessary, as in the case of 
repairs. 

Generally speaking, it shows that you 
are not up to the standard of work required 
in aeroplane construction. 

FINISHING OFF. 
Having properly put the screws in just 
slightly below the surface, the bottom 
flange may now be fixed in precisely the 
same mariner. The rib can now be left for 
half an hour, if another jig is available, 
for the glue to set. At the end of this time 
the rib is ready for finishing off, sand- 
papering, etc ; this work, of course, being 
done by unskilled labour, and on a sand- 
papering machine covered with garnet 
paper. 

8 4 



HOW AN AEROPLANE IS BUILT 



ORDINARY RIBS. 
The next ribs to put in hand will be the 
centre ribs, three in number. These will 
have precisely the same contour or curves, 
and, therefore, the rib template will be 
required again. But another jig-board 
must be prepared. This will be done in 
the same way, only as the web is only A in. 
three ply, and the flanges about \ in. by 
il in., with are in. deep groove in the 
centre of one side to take the -h in. 
three-ply, the packing piece on the rib jig- 
board will have to be reduced in thickness. 
This will allow the edge of the \ in. flange 
to lie level on the jig-board and will ensure 
the flange being central with the web. To 
this it will be attached with 20 gauge by 
\ in. long gimp-pins, and glued. The webs 
will, of course, have to be carefully set out 
as they are lightened in the centre, and 
have also to have the holes cut in for the 
spars to pass through. Otherwise these 
ribs will be constructed in the same way as 
the end ribs. 

THE LEADING EDGE. 
The next thing to put in hand will be the 
leading and trailing edges, which will be 
of spruce with ash tips, V-shaped, with a 
f in. radius at the small end of the V, and 
lightened out at the mouth of the V about 
f in. deep, allowing rein, thickness either 
side. The rectangular section of the spruce 
85 



HOW AN AEROPLANE IS BUILT 
and ash required will be about 1|- in. by 
1 in., to allow for cleaning up about -in. 
full and shrinkage. 

The first thing to do will be to plane up 
a sufficient length of spruce and ash to this 
size and then spindle out the lightening, 
after which it may be cut in the spindle to 
its finished shape (see Fig. 13), leaving 
about 6 in. solid each end for additional 
stiffness. 




Fig. 13. 



A PLANE ERECTING JIG. 
Having considered the manufacture of 
all the parts required to construct the 
centre plane, the next thing will be to 
erect it. A completed Centre Plane Sec- 
tion is shown in Fig. 14. As very con- 
siderable accuracy and squareness is re- 
quired, it will be necessary to do this work 
also in a jig, as these centre sections must 

86 



HOW AN AEROPLANE IS BUILT 




HOW AN AEROPLANE IS BUILT 
be absolutely interchangeable with each 
other, and square. Therefore, a small jig- 
table must be prepared in a manner similar 
to the fuselage jig-tables. 

On this set out a centre line lengthways 
of the table, and on this line, at right-angles 
to it, set out the centre line of the com- 
pression spars. Then carefully with a 
gauge mark the centre line on the ends of 
each spar when it is standing on one of its 
narrow sides. Lay the spar on the jig- 
board and see that the centre lines on the 
spar and jig-board coincide exactly. Then 
clamp them down, and screw hard wood 
stops on each side to keep them there, 
taking care not to put the stops in the way 
of ribs. Also fix end stops to locate the 
compression spars in the centre. Then 
very carefully check the measurements in 
between after having completed the stops 
for holding the spars. 

The next thing to do is to glue and screw 
four pieces of packing under them, namely, 
two near each end to raise them up off the 
jig about \ in. This is necessary to enable 
the bottom flange of the rib to slide into 
its position on the spar. To prevent the 
ribs from being pushed on too far, or being 
out of parallel with the centre line, limit 
stops must be fixed, so that the ribs can 
only be pushed on to the spars a definite 
distance, with absolute accuracy. Turn- 
buttons with a fairly long sweep must be 

88 



HOW AN AEROPLANE IS BUILT 

fixed to keep the outside ribs up to this 
position. 

Having done this, the next thing to do 
will be accurately to locate the three light 
centre ribs, and fix stops each side of them 
to hold them in position on the spars, for 
fixing. If all these things are done it will 
be impossible to build the centre plane 
incorrectly, provided the stops have been 
accurately placed in position, and the ribs 
and spars made correctly. 

All that now remains is to get the jig 
passed by the inspection department, and 
assembling can then be commenced. 

ASSEMBLING. 

The first thing to do is to mark off the 
bolt holes on the spars for the wiring 
plates and strut eyebolts and get them 
drilled, preferably on a drilling machine. 
This being done, slide on the three light 
centre ribs, then bolt on the wiring plates 
to the spars, and attach the swaged wires 
to them, at one end only ; then slide on the 
compression end ribs. 

Then place the whole over the jig and 
adjust each component part and drop the 
lot into their respective positions in the 
jig. Screw each in position, and give a 
touch of glue to each one, then leave the 
whole to set. 

When the glue is set the centre plane can 
be taken out, the leading and trailing edge? 
8 9 



HOW AN AEROPLANE IS BUILT 



fitted, the bracing wires coupled up, the 
tension adjusted, and the whole plane 
finished and sand-papered off, ready for 
covering with fabric, with the exception 
of fixing the four eyebolts for attaching the 
plane to the vertical centre plane struts. 

BOTTOM MAIN PLANES. 

The construction of the bottom main 
planes must now be considered, and the 
first thing that has to be done is to produce 
the front and rear spars, which we will as- 
sume to be 19 ft. 9 in. and 19 ft. 3 in. long, 
respectively, by 3^ in. by 2 in., tapered at 
the outer ends and lightened in the web 
where possible to H or girder section. 

First-class spruce must be selected, and 
the timber cut so that a vertical grain is 
obtained when the spars are finished and 
lying in their natural position, the mini- 
mum number of vertical grains per inch 
being not less than 6 per inch of width. 
They must have no short or twisted grain, 
and must be free from any faults such as 
" feathers " in the grain, sap, dead wood, 
shakes, splits, knots, or pockets of resin, 
however small. 

As the A.I.D. may be relied upon to give 
these a severe testing and a rigid inspec- 
tion, it is not advisable to cut up faulty 
timber and work it up in the hope of getting 
it passed. 

Having selected the timber, it will "be 

90 



HOW AN AEROPLANE IS BUILT 



marked off, and taken to the circular-saw 
and sawn into the required rectangular 
section and length plus about Q in. for 
cutting and finishing off ends. 

These sides will be planed and the edges 
shot ; they will then be sent to the setter- 
out, who will set out the lightenings on a 
template of the length and width of the 
spar, but § in. or f in. thick, preferably 
of hard wood. The outer end will be 
tapered to suit the diminishing depth re- 
quired in finishing off the tip of the wing 
where it cuts the leading edge. 

MACHINING OUT. 
The lightenings having been marked off 
on the actual spar, a template or section 
of the finished spar, where the lightenings 
occur, should be made and sent in to the 
mill to the spindle hand, who will prepare 
the cutters, and spindle out a short length 
of spar to test the dimensions of the cut. 
This being correct, the spars may be 
lightened out as far as the straight portions 
go. 

After which the spar template must be 
placed on the spar and the curved portion 
carefully marked off. Then the spar must 
be sent to the band saw to have this por- 
tion cut to the curve, and it can then be 
finished off on the spindle or bench, as 
may be more convenient, or sent to the 
wood-finishers' benches. 



HOW AN AEROPLANE IS BUILT 
It will then be ready for the spindling 
out of the lightening to be completed, as in 
Fig. 15. 

BEVELLING OFF. 
The last operations to be done to com- 
plete the spars for use will be to bevel the 
edges slightly right across to fit the contour 
of the ribs. As this bevel will be a definite 
angle and will probably be specified in de- 
grees and half degrees, a bevel protractor 
will be required to set out and check this 
operation. Careful reference to the plan 
should be made to ascertain the amount of 
bevel required. This work may either be 
done on the planing machine or the 
spindle. 

A DELICATE OPERATION. 
The bolt holes for the wiring plates must 
now be marked off, also the holes for the 
strut eyebolts, which go vertically through 
the spars. 

Before drilling these bolt holes it is ne- 
cessary to point out to all concerned, that 
the importance of these holes being drilled 
perfectly cannot be over-estimated, and 
unfortunately, there are many who, being 
new to aircraft work, get an idea that the 
works manager, foreman, or inspectors, 
who point this out, do so either for the sake 
of talking or of showing their authority. 
This is not so. The holes must be drilled 
out in one dead straight line, and not 

92 



HOW AN AEROPLANE IS BUILT 




03 



H OW AN AEROPLANE IS BUILT 
started from each end, and allowed to meet 
"somewhere" in the middle, nor as is 
done occasionally, may an old bolt be 
driven through to clear the hole. This sort 
of work is not wanted, neither are " rat 
holes." 

The holes must be accurately bored or 
drilled with a sharp cutting tool, exactly 
where they are required, and no limits are 
allowed for deviation, therefore it is advis- 
able for all bolt holes to be bored by an 
accurately running sensitive drilling ma- 
chine, bolted down to a firm foundation. 
Accurate work is not to be obtained from 
machinery attached to wooden floors in 
galleries, as is found in some works. 

FINISHING THE SPAR. 
Having completed the holes, the last 
work to be done is to taper the end of the 
spar down to the point where it meets the 
leading edge, and this will be done by the 
wood-finishers' department, before going 
to the erecting shop. This being done, it 
can now be inspected and passed by the 
A.I.D. 

WING SECTION ON TRESTLES. 
The construction of the wings may now 
be considered, as the manufacture of ribs 
has been previously dealt with, and also 
the leading and trailing edges. For this 
work some light trestles, three in number, 
will have to be made, about 3 ft. high and 

94 



HOW AN AEROPLANE IS BUILT 



3 ft. 6 in. wide, of 1 in. boards, on edge, 
screwed to the floor with light iron knees 
and braced together with a light longi- 
tudinal, bracing about 3^ in. by 1 in. In- 
clined bracing will connect the longitudinal 
bracing to the vertical leg of the middle 




SKETCH SHOWING WING CONSTRUCTION . 

Fig. 16. 

trestle. The trestles being completed the 
erection of the wings can be commenced. 

Take the spars and lay them in their 
correct positions on the trestles and mark 
off the positions of the various ribs, of 

95 



HOW AN AEROPLANE IS BUILT 
which there will be about four different 
types. Commencing from the root of the 
wing and working outwards to the tips, we 
shall have the following : first, an extra 
strong rib with a solid web, then a number 
of ribs of a light design, with three-ply or 
lightened spruce webs, and then another 
rib with a solid web, where the joint occurs 
between the rib and the aileron. 

After this, we have a number of ribs with 
the trailing end cut off where the rib flange 
reaches the rear side of the rear spar. 
The aileron makes up this portion, and is 
attached to the rear wing spar by about 
four hinges, which are attached to the wing 
spar and the aileron spar by bolts. 

As each type of rib has a drawing 
number and part number, it will save a lot 
of confusion if the position of each rib on 
the spar has the drawing number and part 
number stamped on it with a rubber stamp, 
as this will enable any unskilled labour 
which may be employed in the erecting 
shop to place the right type of rib in the 
right place, and prevent mistakes and 
disputes. 

Having marked off the positions of the 
ribs, the next thing to do is, make a list of 
the ribs required, and the number of each 
type required, and obtain these from the 
finished wood parts stores, and examine 
each one to see that it has been inspected 
and stamped by the A.I.D. It will be as 



HOW AN AEROPLANE IS BUILT 

well to keep the list of ribs for future use. 

We can now thread the ribs carefully on 
the spars. In some cases we shall, no 
doubt, find that the spar holes in the webs 
of the ribs require easing. This can be 
done with some sandpaper wrapped round 
a stick. 

The first ribs to be put in, will be the 
ribs in the centre of the wing. Then 
work outwards towards each end. Having 
threaded all the ribs on the spars the front 
spar should be clamped down to the 
trestles, and the mark of the rear spar end 
carefully squared off with the end of the 
front spar. These ends refer to the root 
of the wing, next to the fuselage. 

This being done the ribs can be fixed to 
the spars by means of small brass screws. 
Each of the ribs should be tested with a 
square to make sure they are square with 
the spars. 

WIRING UP. 

The ribs being fixed, the wiring plates 
can be bolted in position and two or three 
bays of wire bracing put in, to keep the 
wing in shape. 

It will be as well now to thread the 
stringers in position. These consist of 
long lengths of spruce about tf in. 
square, which run parallel to the spars, 
and pass through the webs of each rib just 
under the rib flanges. 

We can now turn our attention to the 

<J7 

G 



HOW AN AEROPLANE IS BUILT 
leading edge, which consists of spruce 
lightened out to the shape shown in Fig. 12. 
This will be now threaded through the 
noses of the ribs, care being taken, after it 
is in position, to remember to see that all 
ribs remain square with the spars. As 
soon as this is done, the ribs can be 
screwed to the leading edge, and each side 
of the rib, then touched with glue. 

SCARFING THE WING TIP. 
The next thing to do will be to prepare 
the scarfed joint for the junction of the 
leading edge with the ash bend at the tip, 
this will be done by tapering the end off 
for about 7 in., after which the bend can 
be treated in the same way, carefully fitted 
and tried in position. Then the per- 
manent joint with glue and f in. by No. 6 
gauge brass screws can be made. Two 
screws to each side should be sufficient, the 
whole being clamped up and left for about 
10 hours. After that the scarfed joint can 
be shaped up and cleaned off, and left 
ready for binding with balloon cord 
knotted at each turn. 

THE TRAILING EDGE. 
The next thing to do is to fit the spruce 
trailing edge, and this will be done in the 
same way, but without any binding cord 
or similar joint. The strut to the end 
compression rib can now be fitted, also the 



HOW AN AEROPLANE IS BUILT 



small packing pieces between the ribs and 
riblets (small ribs), which are glued and 
tacked down. In some wings this is left 
out. 

FINISHING OFF. 

When the whole lot is done, the next 
thing to do is to go over the whole skeleton 
wing and chisel off all sharp points and 
square corners and file off all projecting 
or rough screw-heads, tacks, and wood 
ends of riblets, etc., etc., and well sand- 
paper all over. After this, the wing may 
be considered ready for final trueing up 
and passing by the works inspector, who, 
if he finds any faulty work, should see it 
rectified. Thereafter the wing is ready for 
passing by the A.I.D., for tapeing and 
varnishing. 

Then it will again be inspected by the 
A.I.D., and covering may be commenced. 



CHAPTER V 



WING COVERING 

The cover having previously been 
stitched up, and all seams carefully ex- 
amined, and the cover being quite dry, 
it will be drawn onto the plane, starting 
from the leading edge and pulling across 
to the trailing edge, half the cover being 
on the lower side of the plane, and the 
other half on the top side. The fabric will 
then be carefully and evenly pulled taut, 
and tacked down temporarily, all seams 
being carefully straightened by pulling the 
fabric at each end. After this, all surplus 
fabric will be cut off and the two ends of 
the fabric sewn up, taking care to turn in 
the edges of the fabric, the joint being along 
the centre of the trailing edge, and, where 
the aileron gap occurs, along the top edge 
of the rear spar. 

STRINGING. 
Having neatly sewn up all the edges, the 
next operation is stringing the wing to keep 
the fabric tight to the ribs. This is done 
with a light, fine string, which is passed 
through the fabric from the top to the 
bottom round each rib about every four 

IOO 



HOW AN AEROPLANE IS BUILT 
inches and knotted at each turn, taking 
care to knot up fairly tight. 

This work, as well as the sewing, will 
be done by girls, and they do it well, after 
having a little tuition, but they always need 
a little supervision. One thing to be 
avoided is making holes with the stringing 
needle where it is not intended a string 
should pass through, the only hole per- 
missible being the one where the string 
passes through. 

When this is done, the plane should be 
weighed to see that it does not exceed the 
standard weight for its type, and is then 
ready for its first coat of dope. 



CHAPTER VI 



DOPING. 

The plane having been brought into the 
dope room, one thing to do is to see that 
the specified temperature demanded of 
the room exists. The plane is then laid 
on bearers running longitudinally under 
the spars, and these will be supported on 
trestles. The dope then can be put into 
galvanised paint pots, for convenience. 
Special brushes will be required for dop- 
ing, preferably about 4 in. wide. Common 
brushes for this work are useless, as the 
hairs come out and cover the plane, and 
spoil the finished appearance. 

To start doping take a fair amount of 
dope on the brush, and work it first from 
leading edge to trailing edge, and then 
from left to right. Spread it evenly, taking 
care not to start too big a patch at once. 
In this manner cover the whole plane, 
after which the specified time must be 
allowed to elapse before proceeding. 

STRIPPING. 
The next thing to do is " stripping " the 
plane. This consists of again doping the 
line of stringing, and at once laying a strip 
of frayed tape over the stringing onto the 

102 



HOW AN AEROPLANE IS BUILT 



wet dope and finishing off smooth with the 
brush. It is well also to cover the edges 
in a similar manner. 

Allow the whole thing proper time to 
dry, according to the doping scheme em- 
ployed. When dry, the whole should be 
doped again, until it has had about four or 
five coats. When this is done, the identifi- 
cation mark is set out, and the outer circle 
filled in with blue dope or colour, and then 
the red bull's eye. After this is done on 
the undersides of the lower planes, and 
has dried thoroughly, the wing can be 
varnished with the special varnish. 

When this has set, the coat of pigment 
can be put on the top, and, finally, the last 
coat. The plane can then be left to dry, 
the whole of the doping process being 
complete. 

In this manner ailerons, tail planes, and 
elevators will be doped. Other schemes 
are available, and may be worth trying. 



CHAPTER V1J 



AILERON CONSTRUCTION. 

The construction of the ailerons can next 
be taken in hand, for the work of construc- 
tion is very similar to wings. The differ- 
ence is that the spar of an aileron is 
frequently hollow, and made in two pieces, 
very carefully and well glued together. 

The making of this hollow box spar re- 
quires very careful consideration, unless 
undertaken by experienced hands who are 
used to this class of work. 

The timber selected requires to be of 
the best quality, and straight grained and 
dry, otherwise failure may reasonably be 
expected, and a considerable amount of 
time and material will then be wasted. 

The aileron spar we may assume to be 
about 4 ft. 9 in. long and 2\ in. deep and 
about If in. broad. They are made in 
halves, with about six lightenings in each 
half opposite each other. These will be 
cut out on the spindle. 

These two parts form the spar, the 
lightenings being in the middle. The 
whole, when together, will taper down in 
the last third of its whole length to about 
one half of its normal sectional area, the 
ends of the spar, of course, being left 
solid. 

104 



HOW AN AEROPLANE IS BUILT 



In preparing these two halves to form 
the spar a considerable margin of timber 
should be allowed for cleaning up on the 
outside after spindling out the lightenings. 
Also, it is most essential that the halves of 
the spar, after coming from the spindle, 
should be placed in clamps to dry, as this 
timber, being freshly cut out, is likely to 
twist or warp and lose its shape through 
exposure to the air if left to dry in a free 
state. 

The halves of the spar having had a 
couple of days to dry, should now be 
brought to the wood-finishers' benches, 
where the joint faces will have to be care- 
fully tried for truth of surface, and all 
inequalities removed with a trying plane, 
so as to remove as little as possible. 

Having made the joints true, the next 
question is glueing the two halves together. 
For this purpose, glue of special strength 
will have previously been obtained. 

Before spreading the glue, the surfaces 
of the two halves of the spar are frequently 
ironed with a hot iron, so as not to let the 
glue grow cold and partially set before 
the two halves can be placed together. 

Great care indeed must be taken to 
spread the glue quickly and very evenly. 
This should be done with a brush of mode- 
rate size and good quality. After this, 
the two surfaces should be slightly rubbed 
together and quickly and evenly clamped 
105 



HOW AN AEROPLANE IS BUILT 

up and left to dry in a temperature of about 
65 deg. for a couple of days. 

The spars having thoroughly dried, can 
now be taken out of the clamps and sent 
to the wood-finishers, who will dress off 
the outside of the spar to the finished 
dimensions, taking considerable care to 
leave the spar all over a bare -h. in. 
full. 

The spar can now have the holes for the 
hinge bolts and fittings marked off and the 
holes drilled on the drilling machine. 

MAKING THE AILERONS. 

The spar can now be sent to the Works 
Inspection Department, and, if passed, 
sent to the A. ID. Inspector for final in- 
spection, and then sent to the finished 
parts stores, ready for issue to the erectors. 

The ribs for the aileron will be con- 
structed in jigs similar to the rear portions 
of the ordinary long wing rib jigs, pre- 
viously described and illustrated, as the 
aileron forms a part of the outer end of 
the wing, and is of the same contour and 
streamline section. About six ribs will be 
required, including the outer tip rib, which 
will be of slightly different construction 
from the rest, being made with -§-in. three- 
ply web. 

THE TRAILING EDGE. 
The trailing edge consists of an ash bend 
terminating in a long straight portion 

106 



HOW AN AEROPLANE IS BUILT 
which forms the whole of the trailing edge 
of the aileron, the width being about 1 in., 
of tapering cross section, which is about 
| in. thick at the leading edge side, and 
tapering to the trailing edge to \ in. thick, 
this being rounded on the edge, these be- 
ing the finished dimensions. 

Unless the firm carrying out contracts 
involving steam-bending are used to doing 
this sort of work it is best to obtain the 
bends from firms who specialise in this 
class of work. 

In ordering up the required ash bends, 
we should have to specify that the ash 
bends be made out of 1J in. by f in. ash. 
This size will allow of all imperfections 
being machined out, when being machined 
up on the spindle. 

A. surplus of about 15 per cent, should be 
allowed for breakages, bad wood, bad 
bends, etc. 

MACHINING BENDS. 

Having received the ash bends from the 
steam-benders, they can be taken from 
stores and passed into the wood machining 
department. The next thing to do will be 
to get the cutters for the vertical spindle 
made, together with the metal gauge of 
the section ; these having been passed by 
the Inspectors, the work can be proceeded 
with. 

This will be done by passing the bends 
107 



ROW AN AEROPLANE IS BUILT 



past the cutter, in a manner similar to 
that used when spindling the leading edge 
of the wing. 

The trailing edges of the ailerons when 
finished will then be examined by the In- 
spectors, and stamped by the A.I.D., if 
passed. 

ASSEMBLING THE AILERON. 

The first thing to do now will be to as- 
semble the aileron. To do this it will be 
best, if many are to be made, to make a 
couple of jig tables, left and right-hand, 
similar to those used for the fuselage erec- 
tion. This table will be made, and cramped 
together, out of 6 in. by 1 in. flooring, 
covered with about \ in. three-ply sheets. 

The spar can be laid on this jig table, 
and the necessary stops glued and screwed 
around it to keep it in position, taking care 
to miss the position of the ribs. The ribs 
can now be put on to the spar and squared 
up carefully, this being of considerable 
importance, after which they can be glued 
and screwed into their final position. 

The ribs are held in their place square 
to the spar, and prevented from moving, 
by additional stops at the trailing end of 
the ribs, and also at their end next to the 
spar, thus ensuring their being square with 
the spar. 

The trailing edge can now be threaded 
through the ends of the ribs, and the 

noS 



HOW AN AEROPLANE IS BUILT 




HOW AN AEROPLANE IS BUILT 
curved end of the ash bend attached and 
jointed to the spar. This should be done 
first, in case the joining affects the radius 
of the curve. This procedure allows of 
any necessary adjustment being made 

The next thing to do now is to complete 
the fixing of the ribs, this being done by 
the usual method of glueing and screwing. 
After this, the flanges can have their sur- 
plus ends cut off and rounded. The last 
part to be fixed is the spruce stay from the 
spar to the end rib, at the opposite end of 
the ash bend. (See Fig. 17.) 

The aileron can now be inspected, and 
if passed by the Works Inspector, can be 
inspected by the A.I.D. and passed — with 
luck. 

FINISHING. 

The skeleton aileron is now ready for 
painting and varnishing, after which the 
hinge fitting can be attached, when the 
varnish is dry. It can then be inspected, 
and is ready for going to the covering shop 
to have the fabric put on and stitched up, 
exactly as in the wings. 

The doping and varnishing only remains 
to be done. 

The next thing to be constructed will be 
the tail-plane, elevators, the fin, and rud- 
der; as they are constructed principally 
of metal, they will be constructed in the 
metal department, and to this department 
we shall now have to turn our attention. 

no 



HOW AN AEROPLANE IS BUILT 




1 1 1 



HOW AN AEROPLANE IS BUILT 



A RETROSPECT. 
We will, however, for a few minutes, 
retrace our work back to the fuselage, with 
which we commenced. The wood work 
is all completed, and the process of as- 
sembling with fittings which we had not 
made has all been dealt with, and it is now 
necessary for us to consider the various 
methods of making a few of the required 
fittings. 

On referring to Fig. 8, we see from the 
drawing that 12 strut fittings are required. 
In the fuselage, these consist of wiring 
plates, with a square steel shoe welded on, 
which takes the strut end. These fittings 
are simple, but require considerable care 
in making, as aeroplane parts consist 
usually of light designs with small factors 
of safety. Which means that what is made 
must without doubt be made from material 
strictly in accordance with the specifica- 
tion, and absolutely not under the sizes 
and dimensions shown on the drawings. 
• The slightest disregard of this will render 
all parts scrap ; scrap means waste of 
labour and money, so don't forget this, it 
may save time. It is useless to try sub- 
stitutes. Go for absolutely the right thing 
first time, and have it. 



1 J 2 



CHAPTER VIII 



THE MANUFACTURE OF METAL FITTINGS. 

As we have only a small order with 
which to deal, it will be useless to consider, 
at this stage, the production and use of 
punches and dies for the production of 
these parts, as the quantity is insufficient. 

The die and punch would cost almost 
more than the fittings, and probably take 
longer to make than making all the fittings 
more or less by hand. When I say by 
hand, I mean by sawing out on the metal 
jig-saw and filing up to a scriber line or a 
template, whichever method is adopted. 
The template, which is case-hardened, is 
no doubt safer, but it involves time in 
making templates which could be more 
usefully employed in this case on actual 
production, namely, all hands being em- 
ployed on filing up wiring plates to a 
scriber line, and finishing off with a fine 
smooth file, preferably by the most skilled 
hands. 

WIRING PLATES. 
Having considered the three methods of 
production, namely, stampings; rough 
cutting-out, and filing up to a case-har- 
dened template ; or filing up a rough cut- 
ting to an accurate scriber line, I propose 

"3 

H 



HOW AN AEROPLANE IS BUILT 
in this case to use the last, as speed is 
everything in our days. Therefore, I pro- 
pose to detail the organisation and opera- 
tions of producing the wiring plates and 
similar parts by this method. 

We should now refer to the general 
arrangement drawing of the fuselage, and 
from the particulars given thereon ascer- 
tain the drawing and part number of each 
fitting, and obtain the necessary drawings. 
They will be sent to the planning depart- 
ment, who will examine the drawing, and 
ascertain its particulars, such as the ma- 
terial required. 

In this case it will be mild sheet steel, 
to the specification mentioned in the sche- 
dule, and passed by the A.LD. 

The planning department will also detail, 
on the instruction card to be sent into the 
works, the best way of producing the fit- 
tings and the sequence of operations, and 
full particulars of the gauge, etc., to be 
used. They should also, before issuing 
the instruction card to the works, ascertain 
if the material is available in the stores. 

If it is, then they will fill in and issue to 
the stores a material requisition for the 
amount of the metal required to complete 
the fittings and the parts, as ordered for the 
first batch. 

Having done this, the order goes to the 
foreman of the metal shop, and the metal 
is also sent from the stores to the metal 
shop. 

"4 



HOW AN AEROPLANE IS BUILT 



The metal, together with the job and 
instruction card and the blue print, having 
been received, the foreman will then give 
the blue print to the setter-out, together 
with the instruction card. 

The setter-out will then take a piece of 
thin metal, and set out the wiring plate. 
This will, on completion, be sent to the 
inspection department to have the setting- 
out checked with the drawing. It can 
then, if passed, be sent to the template 
maker, who will produce one setting-out 
template. 

When this is done the template will be 
sent to the inspection department. If cor- 
rect, it can then be sent for the final inspec- 
tion to the A.I.D. 

When this is passed, the marker-off will 
mark out on the sheet steel to be used a 
number of the parts as specified on the 
job and instruction card. This sheet of 
steel will then be handed to the operator 
on the metal jig-saw, who should at once 
proceed to saw out the parts set out on 
the sheet of steel, as closely to the outside 
of the scriber lines as is possible, but taking 
care at all times to leave the line visible. 

MANUAL WORK. 
As soon as some of these parts are 
roughly cut out, certain of the bench hands 
should at once be detailed to commence 
finishing these off, and as the remainder of 

"5 



HOW AN AEROPLANE IS BUILT 



the batch come from the metal jig-saw, 
they also should, if possible, be distributed 
amongst further workers. 

In the mean time, any drilling jigs 
needed will have been made. 

By this means a large number of com- 
ponents can be quickly put through the 
works, and passed to the inspection de- 
partment, who, if they find them correct, 
will pass them into the finished part stores. 
In this manner all parts required by the 
erectors can be made ; and, if the progress 
department see that the right proportion 
of parts of various kinds required are made 
each day, there should be perfect pro- 
gress. If there is not, the progress depart- 
ment should adjust and alter the numbers 
of parts demanded from the metal depart- 
ment, or the number of hands employed 
on any special kind should either be in- 
creased or decreased. 

DRILLING PLATES. 

The wiring plates having been filed up 
to shape and finished, the next thing will 
be the drilling of the holes at each end to 
take the A.G.S. pins of the fork ends, 
which are screwed onto the tie rods. 

The necessity for these being perfectly 
drilled in their correct position, and abso- 
lutely at right angles through the wiring 
plates, renders it necessary to construct 
a drilling jig, in which one or two wiring 

116 



HOW AN AEROPLANE IS BUILT 



plates may be drilled at one time, accord- 
ing to the design of the jig. 

A DRILLING JIG. 

An easy way of making a jig is first of all 
for the expert setter-out to mark off the 
holes on a perfect wiring plate with the 
greatest possible care. He should use a 
sharply pointed fine centre-punch, and 
" centre pop " the centres of all holes re- 
quired with absolute accuracy, especially 
taking care to hold the centre-punch ver- 
tically over the position of the hole which 
it is intended to drill, as if this is not done 
it will be found that the holes when drilled 
are not accurate, and just a couple of hun- 
dredths out of their correct theoretical 
position. Therefore give this simple mat- 
ter the attention it richly deseres, as if 
this is not done it gives the small twist drill 
a lead off in the wrong direction. 

Having done this, take a pair of fine 
spring dividers and set out the outside 
diameter of the hole, just a shade larger 
than the true size, so that when commenc- 
ing to drill the hole, before allowing the 
drill to cut its full diameter cut, it will be 
possible on examination to satisfy yourself 
that the hole when drilled will be truly 
concentric with the small circle made by 
the spring dividers. If it is not concentric, 
alter it, or, as it is known in drillers' lan- 
guage, " draw the hole," to its correct 
position. This is done by means of a small, 



HOW AN AEROPLANE IS BUILT 
accurately ground, diamond-pointed 
chisel, cutting a small chip out of the side 
to which it is intended, or necessary, to 
draw the hole. 

PREPARING THE JIG. 

Assuming that we have drilled the wiring 
plate with a^-itt. drill in all holes, irre- 
spective of their final required size, this 
operation only being done for the purpose 
of assisting us to produce an accurate drill- 
ing jig, take the wiring plate and lay it on 
a piece of f-in. or ^-in. thick steel plate, 
say in this case about 6 in. by 3^ in., pre- 
viously carefully levelled by shaping up 
each face parallel to the other, and locate 
the wiring plate in the centre as near as 
possible. This plate will ultimately be- 
come the jig. Clamp it there, and accu- 
rately mark the holes off the wiring plate 
onto the jig-plate. 

Having done this, unclamp the wiring 
plate, and with the spring dividers set out 
a J in. circle round each centre-pop so 
that when you commence drilling you can 
see that the drilling is going to be accurate. 

The^-in. holes having been drilled in 
the | in. steel plate, take the wiring plate 
and lay it again on the steel plate, and 
either rivet it in position, with a rivet at 
each end, and if possible one in the 
middle, or bolt it on. This being done, 
the jig-maker can fit a semi-circular piece 
of steel, J in. thick, round each end of 

11S 



HOW AN AEROP LANE I S BUILT 
the wiring plate lugs, to keep it in position, 
leaving each piece big enough to be drilled 
and riveted in position. 

These pieces having been fitted, the 
next thing to do is to fit a \ in. piece, or 
strip, of steel to each side of the wiring 
plate, and when accurately fitted, rivet 
them to the f in. steel plate. The four 
pieces thus fitted form a bed for the wiring 
plates to be dropped into, say, two of 
them, or any other number according to 
the gauge of the steel. 

This work having been completed, re- 
move the temporary rivets from the wiring 
plate, and enlarge the holes previously 
occupied by the A in. rivets, in the 
steel plate and the other holes, to a size 
equal to about A in. bigger in diameter 
than the required size specified on the 
drawing. 

This is done to enable the hardened 
steel drill guides, or bushes, to be fitted 
into the holes drilled in the f in. steel 
plate. These are necessary because an 
ordinary hole is liable to wear out of shape, 
and cause inaccurate drillings, and, as 
these bushes are removable, they can al- 
ways be replaced with new ones when 
worn. 

MAKING DRILL BUSHES. 
The hardened steel bushes should be 
made to the following dimensions. As- 
suming the diameter of the hole in each end 



HOW AN AEROPLANE IS BUILT 
of the wiring plate lugs is T 3 6 in., it follows 
that a re in. twist drill will be used. 
Therefore the hole in the hardened steel 
bush will be drilled T 3 6 in. The depth of 
the bush should be about equal to five dia- 
meters of the drill, which means in this 
case rf in. The walls of the bush may be, 
say, i in. thick each side plus re in. hole. 

The total diameter of the bush will, 
therefore, equal rVin., the length being 
equal to the thickness of the jig plate, 
namely, | in., and finishing up with a 
square shoulder, say, of £ in. wide, making 
the total diameter of the bush about H 
in., with the entrance to the 1% in. hole 
nicely rounded. 

These bushes will be a pressing fit into 
the holes in the f in. plate. 

Having fitted similar bushes to all holes 
in the jig plate, the next thing will be to 
make a cover plate over the bottom of the 
jig to keep in the wiring plates tightly whilst 
they are being drilled. For this purpose 
we can use a piece of plate about J in. 
thick, fitted with two hinged bolts and wing 
nuts, which fit into slots in the upper plate. 
This allows the wiring plates to be drilled 
in this jig being tightly clamped up to the 
underside of the drilling jig plate, accu- 
rately in position. Having fitted this plate 
the jig can be tested, and if found correct, 
can be put into general use in the machine 
shop. (See Fig. 19.) 

120 



HOW AN AEROPLANE IS BUILT 



These jigs, although involving some 
trouble to make, very quickly pay for 
themselves, as the drilling is accurate, and 
thus no wiring plates will be scrapped, 
which is the principal point in our days, 
when time and material are scarce and 
rapid production is essential. 




SED FOR WIRING PLATES RIVETS 
SECTION ± 



^■WIRING PLATE BOTTOM PLATE OF JIG ^ 

DRILLING JIG 

Fig. 19. 

fuselage strut sockets. 
Having completed the drilling of the 
wiring plates and bent the lugs, the next 
thing to make is the small square steel shoe 
which has to be attached to the wiring plate 
by either brazing or welding. This shoe 
is necessary as a stay or bed for the strut 
end. 

The way this may be made is to take a 

121 



HOW AN AEROPLANE IS BUILT 
strip of steel equal in length to the total of 
the four sides plus an eighth for bends, 
and bend it round a steel mandril of the 
correct size, and weld the joint together. 
After this, the ends may be trued up until 
the shoe is J in. deep. It can then be 
clamped onto the wiring plate in its cor- 
rect position, and welded in the welding 
shop by the oxy-acetylene welding process. 
It should be noted by all that the welding 
must be neat and thorough, as no riling of 
welded work is permissible under any cir- 
cumstances ; and considerable care must 
be taken by the operator not to overheat 
or burn the fitting. 

ANNEALING. 

The batch of fittings having been com- 
pleted, the next thing to do is to anneal 
them in a gas-fired furnace, so that they 
may be of the correct hardness or softness. 
Many excellent types of these furnaces 
are made by some of the best firms making 
gas fittings and apparatus. 

The annealing furnace must, of course, 
be fitted with a pyrometer of an approved 
design, and, although expensive, these in- 
struments pay for themselves, because they 
prevent fittings from being unnecessarily 
over-heated, and prevent gas from being 
wasted. They also let one know that the 
correct temperature has been reached, and 
they therefore prevent fittings which are 

122 



HOW AN AEROPLANE IS BUILT 
imperfectly annealed from being used, 
which, of course, is a safeguard to the 
firm's reputation. They are, of course, 
required by the A.I.D. 

Gas furnaces require handling in an 
economical manner, or considerable waste 
of gas is possible, and they soon become 
an expensive item in the firm's charges. 
It would hardly be advisable to light up 
the furnace for a couple of small fittings, 
so one should wait, if possible, for a fair 
batch of them. It is not advisable either to 
purchase too large a furnace at first. 

FURTHER THOUGHT. 

Having outlined a generally accepted 
method of producing wiring plates of one 
kind, it is superfluous, almost, to add that 
this method may be adopted with certainty 
of quick production, to most other kinds. 
Of course, there are sheet metal fittings 
which really require the skill and thought 
of an expert sheet metal worker, and in 
many cases it is frequently necessary to 
experiment as to the best methods to be 
adopted. Two or three attempts may have 
to be made before a fitting is produced 
successfully, and in such a manner as per- 
mits of repetition work. 

There are many methods of making 
things, but in our days, unless they are 
capable of being used on a commercial 
basis, they are useless, and further experi- 
menting and thought are necessary. 

T2 3 



CHAPTER IX 



BOLT MAKING. 

Assuming that the wiring plates used in 
the construction of the fuselage have been 
made, and bent, and passed into the 
finished part stores, the next question to be 
considered is, are the bolts in stock? If 
they are, so much the better, but it is quite 
probable that about a couple of days before 
they are wanted somebody may have dis- 
covered that only half the quantity have 
been delivered, and that it is uncertain 
where the next lot will come from. We 
will therefore assume that the hexagon 
steel bar required for making these bolts 
is in stock or can be obtained quickly. 

Under these circumstances, it is decided 
to make an immediate start on production. 
The capstan lathe selected for the purpose 
will be a f-in. capstan, fitted with wire 
feed, and with suitable colletts, which is 
the technical term for the jaws in the chuck 
which grip the bar which is to be turned 
down into bolts. 

The bar steel being available, a length of 
6 to 7 ft. will be fed through the support 
attached to the lathe head on the left-hand 
side of the lathe and right through the 
lathe head until it comes through the col- 
124 



HOW AN AEROPLANE IS BUILT 



letts to where it comes in contact with a 
stop in the capstan head. 

The next thing to do is to prepare the 
cutting tool, for cutting down the bar to the 
required size of the bolt. 

The capstan lathe not being provided 
with tools, it will be necessary to obtain 
what is called a box tool holder, which has 
a shank turned down to fit into the capstan 
head, and into the box tool holder is fitted 
the cutting tool and the Vee guide or sup- 
port for the turned bar as it passes the 
cutting tool. (Fig. 20.) 

CAPSTAN SETTING. 

The cutting tool is put into the box tool 
holder and held in position by means of 
a set-screw screwed down onto the top of 
the small piece of high speed steel forming 
the tool. This tool is formed in various 
ways, according to the ideas and experi- 
ence of the capstan setter-up. Some pre- 
fer to fix the tool up to cut level with the 
axis of the steel bar, and others prefer to 
have the tool inclined upwards at an angle. 
This detail, however, will be settled by the 
foreman of the machine shop. 

The next tool to be fitted into the cap- 
stan head tool holder will be the circular 
button die and holder, with special dis- 
engaging head, so that the operation of 
screwing can be stopped practically in- 
stantaneously at the end of the desired 

125 



HOW AN AEROPLANE IS BUILT 



length of screwed thread. The reversing 
of the capstan for unscrewing the die can 
be done by hand or with a slow reverse 
belt drive, whichever is more convenient. 

The next tool to be fitted will be the 
cutting-off tool, or parting tool, in the cross 
slide, for the purpose of parting off the 
newly turned bolt from the bar. 

All the stops for the semi-automatic 
working of the capstan having been ad- 
justed and locked with the lock-nuts, the 
next thing to do will be to attempt to make 
the first bolt. Of course, the first few may 
be expected to be failures, as various ad- 
justments will have to be made until the 
correct diameter of the turning is arrived 
at, and also till the screwing, parting off, 
etc., have been tested. 

CAPSTAN TURNING. 

It will possibly be as well to detail the 
operations, which can be carried out far 
more quickly than it takes to write it. 

The first thing to do will be to start the 
lathe, turn on the " cutting compound " 
so that it thoroughly lubricates the front 
turning tool, catch hold of the long lever 
which operates the slide carrying the cap- 
stan head tool holder, and press the turn- 
ing tool up against the hexagon bar steel, 
thus reducing it to the required size and 
length, which are determined by the stop. 
126 



HOW AN AEROPLANE IS BUILT 




KNEE TOOL HOLDER 




SELF -RELEASING DIE HOLDER 




3 



BOX TOOL HOLDER. 




DRILL CHUCK 

Fig. 20. 

127 



HOW AN AEROPLANE IS BUILT 



Having completed the turning down of 
the hexagon steel bar to the required dia- 
meter and length, which, by the way, is all 
done in one cut, comprising the roughing 
and the finishing cut, the next operation is 
to reverse the movement of the lever, and 
move the capstan head back. 

This movement brings into position the 
button die, or what is frequently used, 
when obtainable, a geometric die head, 
containing the dies. Pull the lever for- 
ward, and gently but quite firmly press the 
die up against the end of the bolt. The 
die will then commence to cut the thread. 
Continue pressing until the lever will travel 
no further. The die will continue to cut 
probably a couple more threads, and then 
the die head will automatically become 
disengaged from the hollow die head 
holder, and will continue to travel round 
with the bolt. 

Reverse the belt drive, if fitted, as it 
should be, and the die will work itself off 
the bolt. 

Having completed the cutting of the 
thread on the bolt, it now remains to part 
off the bolt from the bar. For this purpose 
we now turn to the cross slide and take 
hold of the feed handle and bring the tool 
up against the hexagon bar, which 
promptly cuts off the bolt, which falls into 
the tray underneath. 



128 



HOW AN AEROPLANE IS BUILT 



CHAMFERING. 
Assuming that a number of these bolts 
have been made, they will have to be taken 
to another capstan lathe, if available, and 
there have the heads faced off and cham- 
fered. This is done in one operation by 
the tool fitted into the cross slide tool 
holder. The operation consists of picking 
up the bolt and slipping it, thread first, 
into the jaws of a collett and then pressing 
the tool in the cross slide across the face 
of the hexagon head of the bolt, and clean- 
ing off the head and chamfering. This 
operation having been completed, the bolt 
is taken out, and the operation of bolt 
making is finished. 

NUT MAKING. 
The bolt will now require a nut, and the 
same sized hexagon bar will, of course, 
be suitable for making the nuts. The set- 
ting up of the capstan for nut making con- 
sists of fitting a stop for adjusting the feed 
of the bar, thus allowing only the correct 
length of bar to be fed through. Having 
done this, a tool for facing and chamfering 
the nut should be fitted into the tool holder 
of the cross slide on one side, and a part- 
ing-off tool in the tool holder on the oppo- 
site side. 

Also a centre bit can be fixed in the 
capstan head tool holder, for giving the 
129 

I 



HOW AN AEROPLANE IS BUILT 



twist drill, which is also in the capstan 
head, a true start. This twist drill is, of 
course, a tapping size. 

The procedure of work consists first of 
facing and chamfering the head of the nut. 
This being done, centre the nut with the 
centre bit ready for drilling. Then reverse 
the lever and bring the twist drill into 
operation and drill the hole through nut. 
When this is done, part off the nut, which 
can be tapped in a small jig in a tapping 
machine, which is quicker than tapping in 
the capstan lathe. 

The time taken to produce, say, J in. 
bolt and nut, about 2\ in. to 3 in. long, may 
roughly be assumed to be about four 
minutes. From this it will hardly be neces- 
sary to point out how very valuable a few 
capstan lathes, or even one only, can be 
in a workshop, in case of delay in delivery 
of bolts from the recognised manufac- 
turers. 

MAKING EYEBOLTS. 
Eyebolts are made in precisely the same 
way, only that round steel bar is used 
instead of hexagon, and the parting-off 
tool is shaped so as to produce a semi- 
circular elongated end. The bolt is then 
put into a milling jig or clamp and the head 
milled between two milling-cutters. This 
can be done with batches of, say, about 
eight at a time, after which each batch is 
put into a drilling jig and drilled. 

T 3 



HOW AN AEROPLANE IS BUILT 
Should the eyebolt require to have the 
eye at a certain angle, then of course the 
jig which holds the eyebolt during the mill- 
ing process is made to hold the bolt at the 
required angle, and thus accuracy is ob- 
tained. The accuracy of this angle is most 
essential, otherwise a fair pull is not ob- 
tained by any tie rod or streamline wire 
which may be attached to it, and inac- 
curacy may start a dangerous fracture. 

To the inexperienced erector this item 
may not appear to be of much importance, 
but it happens to be one of those matters 
which strictly demand the attention of all 
erectors. It applies to wiring plates as 
well, which must be bent to suit the angle 
precisely, between the two points of at- 
tachment of any tie rod or streamline wire. 

SNUGS. 

Reverting again to eyebolts, many of 
these are made with a " snug " under the 
head. This, to those who are not familiar 
with this term, consists of a projection to 
prevent the bolt from turning round when 
in its correct position. This operation in 
the manufacture of eyebolts is usually done 
by using a dividing head attached to a mill- 
ing machine table. This holds the bolt in 
position whilst the milling cutter produces 
the required shape, which in many cases 
may be described as a semi-elliptical pro- 
jection, about rs-in. deep. 

131 



CHAPTER X 



LIFT PLATES. 

Lift plates, i.e., those which take the 
main load or flying wires of the machine, 
frequently consist of laminated plates sol- 
dered together. These have to be made 
with considerable care, as much experi- 
ence is necessary in knowing the additional 
amount of length required to allow for 
bending, so as to enable the various holes 
to be drilled accurately in position. 

To enable this to be done, it is necessary 
to pin the laminations together and put the 
fitting in a jig to be drilled, after which it 
is best to use a cast iron or mild steel block, 
designed to be used as a bending jig. It 
will be almost impossible to describe these, 
as of course they are very numerous owing 
to the number and various types of fittings 
to be bent. Accordingly it is best to get 
the tool-maker to design one specially to 
suit the particular fittings required to be 
bent. 

The value of a small fly press is consider- 
able for many small parts, and, with simply 
designed jigs, an intelligent youth can pro- 
duce a considerable number per day of 
small washers, etc. 

132 



HOW AN AEROPLANE IS BUILT 



CHASSIS STRUT FITTING. 

The chassis strut fittings will now be re- 
quired, and these will require careful 
thought, as they are made to grip the lower 
front spar, and at the same time pass round 
the compression strut. The first thing to 
do in making fittings of this description is 
carefully to set out the whole fitting on 
some light gauge, black-iron or steel, and 
bend up the fitting and tack it in shape by 
welding it together. 

After this the portion for holding the 
chassis struts can be set out on the flat plate 
and bent up to the required streamline 
shape. Then the angle required by the 
strut can be checked. 

This having been done, the fitting and 
manufacture of this part must be com- 
menced. For this purpose, and to assist the 
sheet-metal worker or fitter employed, it 
would be as well to have a dummy portion 
of the front spar fitted onto a dummy com- 
pression spar, so as to enable the metal- 
worker to grasp what to do. 

Also a couple of rejected struts (which, 
of course, should not exist) may be cut to 
dead size in the wood -finishing depart- 
ment, and handed over to the metal de- 
partment, so that they can be actually 
placed into the position and fittings made 
for them, and thus it will enable the worker 
accurately to discover the dimensions to 

r 33 



HOW AN AEROPLANE IS BUILT 
which he has to work. It will also ensure 
the streamline portion of the fitting which 
holds the strut being accurately fitted to 
the portion clipping the front spar and the 
compression strut. 

ACCURATE FITTING. 

This accurate fitting is most necessary, 
otherwise the joint between the two fittings 
will be a very bad one, and this might lead 
to disaster at any moment if the machine 
landed on rough ground. This might occur 
for any of the following reasons : either the 
acetylene-welded joint between the two 
component parts forming the fitting might 
be weak, and badly fitted to enable the 
right-angle of splay to be obtained, 
in which case there would be gaps to be 
filled up with the welding ; or else the strut 
may never have been normally and na- 
turally at the right angle, and may have 
been strained or forced into it. This pro- 
cedure would either badly strain the fitting 
or the strut, and possibly both, and the 
ultimate result would be a bad failure, 
possibly at some critical moment. 

Therefore it can easily be seen that the 
fitting and making of such fittings as I have 
briefly described requires patience and 
care, and the first one or two will in all 
probability take double the time to make 
that the last ones take. But that cannot 



HOW AN AEROPLANE IS BUILT 



be helped ; accuracy and perfect work- 
manship must be had. 

The above remarks equally apply to the 
fitting to be made for attaching and holding 
together the two struts in the Vee shape 
in accordance with the design, and also for 
holding the steel tube forming the axle 
and the shock-absorber fittings. 

The steel tube which forms the axle is 
usually of air-hardened steel, and the 
drilling of the holes in it, for attaching the 
" rubbing plates," or distance washers, 
against which the chassis wheels rub, and 
by which they are kept in position, entails 
considerable trouble owing to the hardness 
of the steel. I have found by experience 
that frequently a shop-made flat diamond- 
pointed drill is superior to any twist drill 
for drilling the holes for the taper pin. 
Turpentine forms the best cutting com- 
pound or lubricant. 

The wheel is kept on the axle by means 
of a large washer, about ft in. thick by 
about 1J in. long, which is an easy push-fit 
over the axle, secured into its place by 
another taper pin. 

These washers are, of course, turned 
out of solid bar on turret lathes, and are of 
the usual class of bar work for which turret 
lathes and capstan lathes are made. The 
washers are usually made by girls doing 
repetition work in the machine-shop. 



*35 



HOW AN AEROPLANE I S BUILT 

STRUT SOCKETS. 
The strut sockets for the centre plane 
will be the next fittings to consider. These 
will take the form of sheet steel streamlined 
sockets on wiring plates, attached to the 
top longerons into which the struts will be 
bedded. The bracing wires will be at- 
tached to the lugs for bracing the centre 
plane. 

These sockets will probably be made of 
18 gauge sheet steel, welded to the wiring 
plate, which will be made of about 12 
gauge steel. As these fittings occupy a 
position of considerable importance, like 
other parts they must be made accurately 
to the dimensions given. Care must be 
taken that the process of welding in no way 
impairs the strength of the fitting. 

Considerable care must be taken to see 
that the wiring lugs are fully up to size, and 
also that all radii on the wiring lugs are 
fully up to dimensions. It is important 
also that the pin-hole in the lugs is cor- 
rectly in position and that the hole after 
drilling is accurately finished to dead size 
with a reamer. These points must be care- 
fully looked to, or you may be sure that 
they will be detected by the A.I.D. in- 
spector. 

The result will be that he will lose his 
confidence in you, and he will conse- 
quently be liable to treat every fitting put 
136 



HOW AN AEROPLANE IS BUILT 
up to him for his inspection with consider- 
able suspicion. This is the most undesir- 
able thing that could possibly happen. If 
possible, try and convince the A.I.D. by 
actual practice that he cannot teach you 
anything, but don't imagine it ; that is fatal ; 
see to it yourself, and don't pass the job 
on for somebody else to do. He may think 
that if you are too tired to do it, it is 
of not much importance, and then the 
trouble commences. 




SPAR ATTACHMENT 

Fig. 21. 



If everybody did their job, I think that 
most^ firms would find that there would be 
considerably less work for everybody to 
do. Shorter hours would be possible, and 
greater output would follow. 

MACHINING SPAR BRACKETS. 
The spar brackets for attaching the lower 
wings to the fuselage consist, for our pur- 
137 



HOW AN AEROPLANE IS BUILT 
pose, of mild steel stampings. These, of 
course, must be machined all over, and the 
lugs, where the hinge pins pass through, 
carefully machined to a specified angle 
with the rest of the bracket so as to give the 
wings the required angle of incidence. 

The best way to machine these is to 
clamp them to a machining jig on the bed 
of the table of a milling machine, about 
four at a time, and pass a couple of side 
and face milling cutters past the jaws of 
the stamping, and then mill out the centre 
portion with a single cutter. When this 
work is complete, they can be transferred 
to another jig and milling machine and 
have the outside surfaces of the jaws 
milled. 

This being done, the next thing to do is 
to mill the lug to the required angle, be- 
tween milling cutters, and then fix the 
bracket for drilling the hinge pin-hole ; the 
lightenings can then be drilled out and 
finished with a round file. The only re- 
maining work to be done is the drilling. 



138 



HOW AN AEROPLANE IS BUILT 




CHAPTER XI 



THE TAIL PLANE. 

The tail plane will now have to be con- 
sidered. For the purpose of this article 
one may assume that the tail plane is al- 
most semi-circular in shape and that the 
framework is formed of light steel tubing. 
This will be in four lengths ; the first piece 
being straight, and forming the base or 
trailing edge of the plane, two pieces of 
tube forming quarters of a circle on each 
side, and one piece forming the centre 
portion of the leading edge, nearly 
straight. 

It may be assumed that the diameter of 
the tube is about f in., and that it is about 
20 gauge. All joints have an internal liner 
pinned in position and brazed. 

This, of course, must be well done, and 
although the oxy-acetylene blowpipe is a 
delightful instrument to do brazing with, 
it may be just as well to point out to all con- 
cerned that its use for brazing is not al- 
lowed by the A.I.D. Of course, there 
may be exceptions to the rule, but these 
exceptions apply to special circumstances, 
which I do not propose to deal with here. 



140 



HOW AN AEROPLANE IS BUILT 



GAS BRAZING. 

Therefore, one has to resort to the gas 
blowpipe, of which there are many makes. 
Those made by the well-known Warring- 
ton firm of Fletcher Russell and Co. may 
be relied upon to do good work, and for 
this light work an |-in. gas blowpipe is 
ample if a good supply of air and gas 'is 
obtainable. Some soft brass wire, or braz- 
ing strip, should be obtained, and although 
borax forms a very good flux, some of the 
brazing compounds now on the market are 
preferable, and in my opinion better re- 
sults are obtainable. 

Having prepared the semi-circular por- 
tions of the tail plane and tested the radii 
in a jig, these may be taken to the brazing 
hearth and the joints brazed and cleaned 
off. After the brazing is complete do not 
do as I once saw done, cool off with water. 
It is decidedly bad practice. Let the job 
cool itself. 

JUNCTION PIECES. 

The next parts to put onto the semi- 
circular portion of the tube will be the 
right-angled junction pieces, which are 
specially-made steel tube fittings, for form- 
ing the connection with the straight tube 
composing the trailing edge of the tail 
plane. These will be pinned and brazed, 
or, as an alternative, sweated on with tin- 
i 4 i 



HOW AN AEROPLANE IS BUILT 



man's solder, after the semi-circular tube 
ends have been accurately cut to length. 

Before this is done, however, slide on, 
into their respective positions, the hinge 
fittings for the elevator flaps, which have 
been milled and bored out of solid bar 
steel. The position of these hinge fittings 
involves working to the very finest limits 
of dimensions, and the greatest possible 
care must be taken to check their position 
before finally drilling, pinning, riveting 
and sweating them into position. 

It is certainly most essential that a steel 
jig be first made and accurately checked 
and passed by the A.I.D., and used after- 
wards to locate the fittings accurately 
whilst being fixed. 

Unless these precautions are taken, the 
tail plane will probably not fit standard- 
ised elevators, which may be made by 
another contractor, and will involve end- 
less trouble to all. 

Before fixing the straight tube into the 
right-angled junction pieces it may be as 
well to try the ribs of the tail plane in their 
respective positions, in case any special 
adjustment of lengths is necessary. This 
having been done, the straight tube may be 
finally fixed and the ribs, which are of box- 
section sheet steel, afterwards fixed and 
riveted into position, when the wooden 
stringer, which lies parallel with the trail- 
ing edge, has been passed through them. 
142 



HOW AN AEROPLANE IS BUILT 



This work being done, the tail plane is 
complete except, of course, for the cover- 
ing with fabric and doping. 

PRESSING TAIL RIBS. 

Having got so far it may be as well to 
give some idea of the construction of the 
ribs and of the method and design for a 
steel jig for making them. 

The ribs, one can assume, are made of 
box-section sheet steel with suitable 
lightening holes, the steel being 24 gauge. 

The first thing to do will be to make a 
steel former of bar steel about f-in thick, 
less twice the gauge of the steel in thick- 
ness, and precisely the same length. The 
next thing to do is to cut out one of the 
steel blanks, out of which the ribs will be 
made, adding to the width the turn up all 
round to form the flange, plus the turn in, 
which will be about f-in. wide. 

Having done this, lay the steel former 
on the blank of steel sheet and carefully 
locate it all ways in the centre. Then mark 
off the bolt holes previously drilled in the 
former, where the lightening holes come in 
the rib, and drill these holes in the steel 
blank. (See Fig. 23.) These two holes, 
in the former and the sheet steel blank, 
are for the purpose of temporarily fixing 
bolts to pass through and to hold the steel 
blank rigidly in position whilst being 
flanged on the former. 

H3 



HOW AN AEROPLANE IS BUILT 
Before proceeding further, it will be 
necessary to make a female former in 
halves out of steel bar to fit on the partially- 
formed rib when the first portion of the 



Fig. 23. 

OUTER STEEL CBAR) FORMER ■ 



I 




\ LIGHTENING- HOLES 

PLAN SHOWING RIB IN .STEEL FORMER 



JOINT 
„ f N 



r 



ex 



.STEEL BAR FORMER 

24 Gauge sheet steel Rig 

.SECTION A 3 




PLAN 



INNER STEEL FORMER 

Fig. 24. 



flange all round has been turned up. This 
female former is for the purpose of pre- 
venting the steel rib from buckling when 
the last operation of flanging is being car- 
ried out. 

144 



HOW AN AEROPLANE IS BUILT 



A COMPOSITE FORMER. 

As the first steel former could not be re- 
moved from the rib when all the flanging is 
completed, it must now be removed and 
replaced with a similar former made in 
five pieces (see Fig. 24). This being 
made in five pieces with the three centre 
pieces, Nos. 2, 3, and 4 removable, it is 
easy to see that when the double flanging 
is complete the work may be removed from 
the bench vice and the centre pieces re- 
moved. Then the two long outer strips, 
1 and 5, can easily be removed from the 
rib. 

What remains then to be done is to 
mark off and cut out the lightening holes 
and finish up with a smooth file. Examine 
the finished ribs and make good any 
buckle, or defects, that may be observed. 

ASSEMBLING. 
After this the vertical sheet-steel web- 
stiffeners may be riveted in position to pre- 
vent the web from buckling under load. 
This having been done, the rib may be 
examined, and, if passed, sent to the 
A.I.D. After which it may, with the 
others, which are of varying lengths, be 
assembled in the framework of the steel 
tube, thus forming the entire frame of the 
tail plane when riveted and sweated into 
position. 

M5 

K 



HOW AN AEROPLANE IS BUILT 
The method of rib making, above des- 
cribed, has given most satisfactory results 
in actual practice, and may be relied on 
generally. The trouble of making the 
steel formers is very quickly paid for 
owing to the speed and accuracy of pro- 
duction, as they permit of moderately- 
skilled workers being employed. 

ELEVATORS. 
The elevators which are attached to the 
tail plane should now be put in hand. As 
they are of similar construction, the only 
difference being the shape and size, it will 
be unnecessary to describe their construc- 
tion in detail. This also applies to the 
rudder and fin. 



j 46 



CHAPTER XII 



CONTROL LEVERS. 

The levers on the elevators and rudder 
we will assume, firstly, are made of mild 
steel stampings. That being the case, they 
must be sent into the metal machine shop 
to be bored out to fit onto the steel tubing. 
This can be done by either " chucking " 
them in a chuck in a lathe, or fixing in a 
drilling jig and drilling Y yin. below size 
and finishing with the correct sized reamer. 

These levers, however, may be made of 
hollow sheet steel, in which case they will 
be edge-welded, with stiffening pieces at the 
ends for attaching the " D " shackles at- 
tached to the control cables. And a steel 
boss will be riveted to the centre for attach- 
ing them to the steel tube, to be drilled and 
pinned thereon. 

In this case a considerable amount of 
work is in hand, and a certain amount of 
experimental work is necessary. The 
drawings should be carefully studied. 
Assuming these levers to be of streamlike 
section, the first thing to do will be to get 
the pattern-maker to make a wooden pat- 
tern for the former, on which will be bent 
and formed one-half of the lever, which we 
can assume to be made out of 20-gauge 
sheet steel. The former should be made, 

147 



HOW AN AEROPLANE IS BUILT 
both male and female, so that the sheet 
steel can be paned out and afterwards 
finished to shape by pressing, or squeezing, 
against the cast-iron former. 

After the sheets have been made cor- 
rectly to shape, they can then have the 
hollow bosses attached to them by means 
of rivets and brazing, the whole being 
assembled for this purpose on a mandril. 

The hollow bosses are of about 14-gauge 
sheet steel, and are generally "spinnings." 
These being an extremely difficult thing 
to make, it is best to obtain them from 
certain firms who make a speciality of this 
class of work, as they would be too costly 
to make, not to say unsatisfactory, except 
in the hands of skilled metal spinners 
equipped with the necessary tools. 

FIXING THE LEVERS. 
The levers which have just been des- 
cribed are required for the rudder and the 
elevators. They are attached to the steel 
tube framing of the rudder and elevators 
by means of taper pins, which are care- 
fully put through the bosses of the levers 
and the steel tube and riveted over. After 
this, the whole is carefully sweated toge- 
ther with solder. This solder must be the 
best tinman's solder, for it forms the 
strongest joint, and flows more evenly and 
neatly than plumber's solder into the small 
crevices and openings. Any superfluous 
solder should be cleaned off with a rag or 
small scraper or fine file while still hot. 
148 



CHAPTER XIII 



TAIL-SKID FITTINGS. 

The various component parts of the rear 
skid will next have to be considered, and 
we can here deal with the most important 
of them. 

The skid-fork will probably be a mild 
steel stamping. This requires to be 
machined up with considerable accuracy 
and precision to fine limits. To proceed 
with the work, it will be best to have the 
socket-end turned down in a centre lathe, 
as it will serve as a gripping piece for the 
jig, which will have to be made to hold 
the skid-fork whilst it is going through the 
operation of being milled. 

For this purpose it must be sent to the 
marker-off and be centred. It can then be 
sent to the metal machine shop, where it 
will be placed between the centres of a 
small lathe, say a 6 in. centre engine lathe. 
Here the outside will be turned down to 
the dimensions shown on the drawing. 

MILLING OPERATIONS. 
After this, the stamping will be sent to 
the milling machine to have the fork-ends 
milled. For the purpose of holding the 
stamping, a heavy cast-iron jig had better 
be made, or a mild steel clamping jig (see 
149 



HOW AN AEROPLANE IS BUILT 
Fig. 25), which holds the socket-end 
firmly, whilst the fork-ends project up- 
wards. Possibly it may be advantageous 
to mill about three fork-ends at once, and 
the jig can be made accordingly if desired. 

The next thing to do is to set up the 
milling cutters on the spindle of the milling 
machine. These will be " side and face " 
cutters, which means that they are capable 
of cutting on the flat face at the side as well 
as on the circumference. 




X MILLING MACHINE TABLE 

5ki0 fork in jig . 
Fig. 25. 



They can be set. up so that they mill the 
outside faces of the fork, and so there will, 
of course, be a fixed overall dimension. 
The distance apart of the cutters must be 
maintained by collars placed between the 
cutters on the spindle, and well tightened 
up to prevent the cutters from slipping 
when the machine commences to cut, keys 
and keyways may be used. 

These two cutters will clean up the faces 



HOW AN AEROPLANE IS BUILT 
of the forks, after which the cutters can be 
replaced with another couple of cutters to 
finish the inside of the fork. Or, if the 
stock of milling cutters happens to be ex- 
tensive, possibly one of the right width can 
be found which will guarantee the accu- 
racy of the width of the cut. 

EDGE FINISHING. 
The next thing will be to finish the edges 
of the fork. These can be done in the 
vice, with a file, by the fitters, but, of 
course, the whole of the work can be done 
on the milling machine, if the stock of 
milling cutters is sufficiently extensive. In 
this case another jig must be available for 
supporting and gripping the fork-ends 
whilst the edges are being milled and the 
top of the forks rounded to the true curva- 
ture. Naturally, this method is preferable, 
as accuracy is guaranteed, but this could 
only be done in a shop with a fair-sized 
machine-tool plant, unless time was no 
object. 

DRILLING THE FORK-ENDS. 
The operation of milling having been 
completed, a drilling jig must be made for 
drilling the holes in the fork-ends for the 
skid-bolt to pass through. 

BORING THE SOCKET. 
Having completed these operations, the 
next thing to do will be to prepare a cast- 
151 



HO W AN AEROPLANE IS BUILT 
iron boring jig which will grip the socket 
end of the fork whilst it is being bored out. 
This jig can be made either to bolt onto the 
face-plate of the lathe or to be stood on the 
table of a large drilling machine, which- 
ever is available for this work, so that in 
the case of a small machine shop, no undue 
inconvenience may be caused (see 
Fig. 26). 







PLAN 










f 
































.-'JIG 


LUG 












f 






TWIST DRILL 




@ 




















1 


















i 

Ttz: 






fOCKET 


b 










i 
i 


SKID FORK 


I 






i 


< 


C ACE PLATE 




( 


LATHE SED 



jig for boring skid fork socket. 
Fig. 26. 

The boring-out having been completed, 
the skid-fork may now be considered ready 
to be sent to the inspection department. 
They should easily pass through here, as 
most of the operations are machine work, 
and, with the male and female gauges to 
check dimensions, accuracy should be 
assured. . 

152 



HOW AN AEROPLANE IS BUILT 



SKID-STAY FORKS. 

The next items are the forks for skid- 
stay, or stay-tube sockets, as some people 
call them. These articles, though simple 
to look at, are not exactly easy to make, 
and may cause a considerable amount of 
trouble and scrap if not manufactured in 
the right way. 

For this purpose they will be made out 
of solid steel bar, turned out to profile on 
a capstan or turret lathe. This operation 
consists of turning down the socket-end to 
the taper shown on the design, and boring 
the fork-end to the profile, the socket leav- 
ing the lathe with the fork-end solid. This 
will have to be cut out on a milling 
machine, and here the trouble commences 
unless a good jig is made which will hold 
the socket-end firmly whilst the fork is 
being milled out. 

The jig for this purpose should consist of 
a mechanism which will grip the taper of 
the socket firmly. For this purpose make 
a strong grip-jig, something on the lines 
of a machine vice, or similar to Fig. 25, 
only with special jaws. This will enable 
about three or four sockets to be done at 
once, all being placed in the jig in a line. 
In this way fairly quick production be- 
comes possible immediately. The drilling 
of the A.G.S. pin-hole in the fork-end will 
necessitate a drilling jig, which can be built 
153 



HOW AN AEROPLANE IS BUILT 
up of mild steel, or cast-iron, whichever is 
most readily obtained. 

THE SKID FITTING. 
The steel-clip fitting for attaching the 
stay tube to the fuselage is made of two 
pieces of 16-gauge sheet steel, each bent 

ALUMINIUM BLOCK 
OR PACKING PIECE " 




STRUT ( O ) SHOE 




STRUT 



SKETCH SHOWING 

STRUT SHOE IN PLACE 
Fig. 27. 

to fit the longeron and also to form the lug 
to which is attached the stay tube. The 
edges of the two pieces forming the lug 
154 



HOW AN AEROPLANE IS BUILT 



are brazed together, with the addition of 
a small washer on either side, the hole 
afterwards being reamered out. The object 
of the washers is to increase the bearing 
area for the attachment bolt which passes 
through. On the inside face of the fitting 
is a steel socket, into which the cross tube 
is fitted. This socket is welded on, and 
into this is fitted the cross tube which forms 
the support for the bearing for the skid 
post. 



CHAPTER XIV 



STRUT-END FITTINGS. 

It will be noticed that at the end of inter- 
plane struts, which in many types of 
machines are made of spruce, a steel fitting 
in the form of a streamlike band or ferrule 
passes round the strut end. Into this is 
fitted an aluminium packing piece, which 
fits onto and forms the connection between 
the eyebolts, which pass through each 
spar, front and rear. This packing piece, 
with the band, keeps the struts into posi- 
tion and takes the thrust. 

This streamline band is formed of about 
20-gauge sheet steel in one piece, the two 
edges at the rear or thin end of the stream- 
line being butted together and welded. 
This welding must be well done and neat, 
as no filing nor cleaning up of welded joints 
is permissible. Afterwards it must be well 
annealed. 

MAKING STRUT SOCKETS. 
The best way of making these strut 
sockets is to have a cast-iron former cast, 
the pattern being equal in length to about 
9 inches of the spruce strut at each end. 
This being cast, it must be carefully 
cleaned up, and then it is ready for the 
156 



HOW A N AEROPLANE IS BUILT 
sheet steel blank, which is to form the strut 
socket, to be bent onto it and round it. 

Before cutting up sheet steel, it is as well 
to get a piece of zinc, or thin common 
black iron, or tin, and bend it round and 
cut it until the required shape and pattern 
is obtained, after which it can be flattened 
out and used as a template for marking off 




Fig. 28. 



the actual blanks. It may be as well to 
point out, however, that the outer extremi- 
ties of the socket should be left quite full, 
and more or less shapeless, as in actual 
practice it is found to be safer to finish off 
the final shaping after the welding is com- 
plete,. in case of any twist or deformation 
having occurred during welding, as is not 
infrequent. Also, the ends require to be 

iS7 



HOW AN AEROPLANE IS BUILT 
trimmed with a file to suit the aluminium 
packing pieces. Where large quantities are 
required, these are, of course, pressed out. 

This being done, the bolt and pin-holes 
will be carefully set out and marked off 
ready for drilling, and drilled. After 
which the fittings can be considered 
finished and can be sent to the inspection 
department. When finished with here, it 
will be sent to the wood-components de- 
partment to be fitted to the struts. 

PACKING PIECES. 
The aluminium packing pieces which fit 
into the strut sockets are generally made 
off metal patterns, and the castings usually 
obtained are nearly perfect. Thus they 
require very little cleaning up. The only 
machining to be done consists in drilling 
the bolt-hole and milling out the radius slot 
where the eye-bolt fits into the packing 
piece. 

This work is usually done in a small 
milling machine with a milling cutter of the 
required diameter. 

In assembling the strut ferrules and 
packing pieces onto the strut ends, care 
must be taken to see, and make sure, that 
the aluminium packing piece beds onto 
the spruce strut. Unless it does so, it is 
possible that the strut may not do its work, 
and might be the cause of a failure of the 
whole machine. 

158 



HOW AN AEROPLANE IS BUILT 




HOW AN AEROPLANE IS BUILT 



SMALL CLIPS. 

It frequently happens in a large contract 
that amongst the many items called for are 
small clips. These clips may be pipe clips 
or wire clips. Sometimes the clip is semi- 
circular, sometimes square, in fact, they 
are all shapes and sizes, but each clip of 
any certain type or size must naturally be 
strictly to dimensions and limits. The 
gauge of the metal used in their manufac- 
ture is often very thin. When this is the 
case it frequently happens that it is pos- 
sible for this work to be done by girls. 

To enable girls to manufacture these 
clips, and save the expense of making 
costly press tools which take a consider- 
able time to make and also to save using 
presses on work they need not be em- 
ployed on, it is best to make a few simple 
jigs which can be used in the bench vice, 
and the power obtained from the use of 
an ordinary hammer, or the squeezing 
action of the vice. 

CLIP JIGS. 

Assuming that we require a thousand 
clips to clip f-in. copper petrol pipes, the 
best thing to do is to get two pieces of steel, 
exactly equal in thickness to the required 
width of the clips, each we can say for our 
purpose about 3 in. long by an inch wide. 
File them flat and square all ways, then on 

160 



HOW AN AEROPLANE IS BUILT 



one mark out your clip, and file this up to 
form a female gauge of the pipe clip, only 
leaving it the same thickness as the re- 
quired width of the clip. After this file up 
the other piece to form a male gauge 
corresponding to the other piece forming 
the female gauge. 

When these are complete, put them both 
together and mark off half the thickness 
of the gauge of metal on each one, file this 
off, and you have a male and female gauge 
to suit each side of the desired clips. These 
then form the die and the punch for mak- 
ing the clips. 

The next thing to be done will be to fit 
a couple of pins into the ends of each end 
of the male portion, and then drill holes in 
a corresponding position in the female por- 
tion for them to slip into. This being com- 
plete, all that remains to be done is to cut 
off strips of the metal to be used, a shade 
wider than required, and cut off into suit- 
able lengths, equal to the total length of 
the clip when flattened, plus a small 
amount, which must be the same in every 
case. 

CLIP PRODUCTION. 

Having got so far, it may be possible to 
start production. 

The first thing to do will be firmly to 
grip the female portion of the jig in the 
vice, with the clip side uppermost, then 
drop the other half of the jig onto it, lift 

161 

L 



HOW AN AEROPLANE IS BUILT 



slightly, and slide a piece of metal between 
the two and accurately locate it in the 
middle, a few taps of the hammer and the 
clip will be found to be practically shaped 
up. The next thing to be done is to drill 
the holes in the clip for the attachment 
screws. 

The same jig can be made to act as a 
drilling jig. For this purpose drill the two 
holes through the jig in the required posi- 
tion. These holes will, of course, pass 
through the first clip, and all others can be 
drilled the same way, after which the sur- 
plus metal may be filed off and the clip 
will be complete. 

This method is a simple but effective way 
of producing small clips quickly and accu- 
rately, and can, of course, be elaborated 
if desired. Also the jigs being simple of 
construction, two or three can be made 
quickly, or any jig worn out can be re- 
placed. Also it enables girl labour to be 
utilised, providing the gauge of the metal 
used is not thicker than 18 gauge. 



162 



CHAPTER XV 



ENGINE PLATES. 

The production of the front and back 
engine plates by hand is a job that should 
only be put into the hands of an experi- 
enced sheet-metal worker, as the thickness 
of these being about 10-gauge which equals 
0.128 of an inch makes it a fairly tough job. 
However, it can be done, and is done, but 
it is not like shelling peas. 

The back engine plate, we will assume, 
is of rectangular shape, the edges and 
lightening holes all being flanged at right 
angles to stiffen the plate. Therefore, in 
marking off the plate on the sheet, all 
necessary allowances must be made for the 
flange and bends. This can be easily done 
first before actually cutting out the engine 
plate, in the following manner. 

We can assume that the edge of the 
plate, which forms the top and bottom 
flange, when in position, is about ^-in. 
wide, with re -in. radius. Therefore, 
take a piece of steel plate, 10-gauge in 
thickness, say 5 in. long by 3 in. wide, and 
mark off a -|-in. flange either end, and 
then put it in the vice with a piece of bar 
steel having a fs-bi. radius, and hammer 

i6 3 



HOW AN AEROPLANE IS BUILT 
the steel plate with a mallet over this flang- 
ing jig. 

When this has been done at both ends 
and a J-in. flange accurately formed, hav- 
ing a re -in. radius, take the piece of steel 
out of the vice and measure it over all, 
and find out if it measures 4 in. across the 
two flanges, or if it is more or less, and 
accordingly make your necessary calcula- 
tions and allowances. Doing this will en- 
able you to cut out the plate to the dimen- 
sions required to give you enough material 
to work with, and to enable you to produce 
the engine plate to the precise required 
dimensions. 

In cutting out and flanging the lighten- 
ing holes had better be started and finished 
first, as any buckle or distortion can be 
eliminated in the plate before the impor- 
tant hole for the engine attachment is cut 
out. 

Before commencing to work on the 
plate it is as well to anneal it thoroughly, 
according to the instructions laid down for 
annealing steel plates, after which the 
lightening holes should be carefully set out. 
Take care to leave enough metal for flang- 
ing, plus a margin for cleaning up, after 
flanging. 

All flanging should as far as possible be 
done with hard wood mallets, to prevent 
the metal from being thinned down and 
the surface damaged. 

164 



HOW AN AEROPLANE IS BUILT 



Having completed the flanging of the 
lightening holes the flanging of the edge of 
the plate may next be taken in hand. 

A WARNING. 

Before proceeding further, I think it 
may be advisable to mention to readers of 
these articles that, in marking off steel 
plates, there is a certain danger in using a 
sharp-pointed steel scriber, as I have 
known steel plates which, when marked off 
thus, have, on being bent or flanged, de- 
veloped a distinct fracture along the scriber 
line, and fittings have had to be scrapped 
from this cause. 

To prevent this arising I suggest that a 
hard brass scriber be used as much as pos- 
sible, in place of a steel scriber. Centre- 
pop marks also frequently cause a tear in 
metal. 

FLANGING OUT. 

The marking off of the flange being com- 
pleted, the flanging may be commenced. 
If a wooden mallet be used, then a cast- 
iron or mild steel block can be used as an 
anvil. If a steel hammer be used, then a 
hard wood block must be used. Few 
people seem to realise this. 

Also, it is well to note that the quickest 
way to take twists, kinks, and dents out of 
sheet metal is to hammer it with a steel 
hammer on an end grain piece of wood. 
For some reason best known to themselves 
165 



HOW AN AEROPLANE IS BUILT 



some people prefer to hammer a piece of 
metal furiously on an anvil, which gener- 
ally ends in the metal being either reduced 
in gauge, or dented all over with hammer 
marks. Of course, these look nice, if done 
in an artistic pattern, but, fortunately, we 
have not yet arrived at that stage in the 
manufacture and decoration of aeroplanes. 
We may come to it after the war. 

THE ENGINE HOLE. 
After the flanges are completed and the 
corners welded and the whole plate has 
been tested for squareness and flatness and 
for its general truth, the centre hole for 
attaching the engine may be marked off 
and carefully cut out, and the attachment 
bolt hole carefully and accurately drilled. 
No " allowances " can be permitted at all, 
and dimensions must be worked to very 
minutely. 

In fact, it may be deemed advisable to 
chuck the engine-plate in a lathe and bore 
out the hole finally to ensure its being accu- 
rate. In removing the greater portion of 
the centre of the hole it is advisable to drill 
a considerable number of holes, and cut 
out the centre by chiselling through the 
centre of these holes, if not bored out in the 
lathe. 

The front engine-plate may be dealt with 
in the manner previously described, after 
which each one should be carefully an- 
nealed. 

1 66 



HOW AN AEROPLANE IS BUILT 



ATTACHING ENGINE-PLATES TO FUSELAGE. 

Before drilling the bolt holes in the fuse- 
lage for attaching the engine-plates, it is 
best to clamp the plates in position and test 
their accuracy, and satisfy oneself that the 
plates are dead in the centre all ways. If 
this is not very carefully done, general 
trouble may be expected, especially in 
trueing up the machine ready for flying, as 
it will be impossible to line the. engine up 
true with the fuselage. 



.67 



CHAPTER XVI 



PETROL TANKS. 

The manufacture of the petrol tank 
might now be considered, and, as this has 
to fit in between the longerons, it is neces- 
sary to work strictly to dimensions, or it 
may not fit the position. 

The workmanship must be extra good, 
as it has to stand internal air pressure, and 
all joints, riveting and sweating with solder 
must be perfect, otherwise serious leaks 
may develop and cause fire to break out in 
the air with fatal results. 

The material frequently used is tinned- 
steel sheets of best quality, about 22 to 24 
gauge, riveted up with -^-in. snap-headed 
copper rivets, and best tinman's solder. 

The pitch of the rivets is about 1 in. 
apart. They must be in a dead straight 
line along the joints, and all rivets must be 
very carefully snapped, and all riveting 
must be concentric with the centre-line of 
the rivets, otherwise they are liable to re- 
jection. 

As it is generally a difficult matter to 
replace rivets, any divergence may mean a 
tank being scrapped, which is an expen- 
sive item to the contractor. 

1S8 



HOW AN AEROPLANE IS BUILT 



TANK SHELLS. 

The first thing that can be started is the 
shell. This will be made of two sheets or 
one sheet, according to the size of the tank 
and sheets. The theoretical girth of the 
tank should be most carefully ascertained 
from the drawings and set out on the sheets 
together with sufficient margin for flanging 
and forming the joint at the bottom of the 
tank where the joint is usually placed. 

There are various kinds of joints. The 
simplest, of course, being the lap joint, 
riveted, and sweated after riveting. The 
usual joint is a double-flanged joint, the 
flanges tightly locking each other, and 
sweated with solder each side of plate. 

SIDE PANELS. 
The joint for the side panels is generally 
made in the following manner : — The side 
panels having been carefully cut out to the 
required dimensions, the edges are flanged 
with a i-in. flange. The side panel can 
then be placed inside the shell plates, the 
edge of the flange of the side panel, which 
will be outwards, being adjusted all round 
inside the shell so that the edge of its flange 
is about ^-in. from the edge of the shell 
plate. 

The side panels are soldered in position, 
and the flange of the outer shell flanged 
back over it. After this, the spacing and 

169 



HOW AN AEROPLANE IS BUILT 
marking out of the rivet holes can be pro- 
ceeded with. But before fixing in the side 
panels, or ends, there is a stiffening dia- 
phragm to be put into the tank shell. 

RIVETING ENDS. 

Having marked out the rivet holes for 
the panels, the quickest way to drill these 
will be with a small electric portable drill, 
such as are made by the General Electric 
Company, this work being done on the tin- 
smith's bench. As soon as the drilling is 
complete, the rivets can be put in and care- 
fully riveted over with a small ball-paned 
hammer, and finished up with a small semi- 
circular snap. 

The riveting being complete, the next 
thing to do is to spread a neat film of solder 
over the rivets and into the joint. It must 
be clearly understood that a thin neat film 
of solder only is required, and not a thick 
mass of uneven lumps. 

THE STIFFENING DIAPHRAGM AND FITTINGS. 

The next thing to do is to fix the dia- 
phragm plate to stiffen the shell. 

Before proceeding, it may be as well to 
set out the position of any fittings or con- 
nections, which have to be attached to the 
tank by means of rivets, or other ways of 
attachment, as it will not be possible to do 
so when both the side panels are in posi- 
tion. 



170 



HOW AN AEROPLANE I S B UILT 
Having attached all fittings, the remain- 
ing side panel can be put in, riveted up, 
and soldered, and all rivet-heads lightly 
and neatly floated over with solder. 

REMARKS ON SOLDERING. 

With regard to soldering, what is 
actually required is to consider the solder- 
ing-iron a paint brush, and with it cause 
the solder to flow evenly and cleanly where 
required. I have met some people who 
imagine that the process of soldering con- 
sists of attaching as many isolated lumps to 
the work as possible. 

If any remark is made about possible 
leaks owing to untidy rough soldering, they 
proudly tell you there is plenty of solder, 
which is just what is not wanted. Half the 
quantity evenly spread on clean metal with 
a well-heated iron, thoroughly cleaned, 
and with plenty of flux, does the job a heap 
better. 

TESTING TANKS. 

Assuming that the tank is finished, it 
must now be tested for leaks. One of the 
recognised ways is to neatly fill it with 
paraffin, attach a pressure-gauge to it on 
one of the fittings or outlets, and then with 
a motor foot-pump, or large bicycle pump, 
fill the tank with 10 lbs. per square inch 
air-pressure. Close up all known outlets 
and leave the tank for 24 hours, then note 
fez? 



HOW AN AEROPLANE IS BUILT 
the pressure in the tank, and look for leaks 
and make good. 

JOINING PIPES. 

With regard to preparing copper pipes, 
etc., it occasionally happens that pipes 
have to be joined. Assuming that we have 
a f-in. by 20-gauge copper pipe to join we 
can do this various ways, but no way must 
be adopted that reduces the bore at this 
particular point. Therefore, to overcome 
this difficulty, expand each end of the pipes 
to be joined for a length of j in., then 
obtain a piece of the f-in. by 20-gauge 
copper pipe, carefully cut off 1£ in., square 
the ends, and slightly taper them off, slide 
this piece into one of the expanded ends of 
copper pipe to be joined. This must be 
a slightly loose dropping fit. Then braze 
this liner in. 

Having done this, clean off all super- 
fluous spelter and insert this short length of 
pipe into the other expanded end of cop- 
per pipe, press tightly together, and clamp 
up. Then braze in a similar manner and 
clean off. 

Another way of joining tubes is to ex- 
pand one end only and insert the end of 
the other piece of tube into it and then 
braze. This makes a simple neat joint, but 
some people may not consider it quite so 
strong. 



172 



HOW AN AEROPLANE IS BUILT 



STRETCHING AND TESTING— JOINING AND 
SPLICING CABLE. 

The splicing of steel wire cables for con- 
trols is work that can only be done by ex- 
perienced men. It is simply absolute waste 
to experiment and to attempt to do this 
work if you are not trained to it. But other 
methods of attaching cables to shackles and 
eyelet bolts are frequently adopted for 5, 
10, 15 and 20 cwt. cables in aeroplane and 
seaplane work. 

Before cutting a wire cable, place the 
cable at the point to be cut into the flame 
of a blow-lamp, then bind with thin iron 
wire with two separate bindings, leaving a 
space between each binding of about £ in., 
and cut with a sharp steel chisel. 

A SIMPLE JOINT. 
To make the cable fast to an eyebolt or 
shackle, place the cable through the 
shackle, ring, or eyebolt. Bring about 6 in. 
through. Then bind this 6 in. to the side 
of the cable with 20-gauge copper wire for 
a length determined by the size of the 
cable, the bindings being about ts in. 
apart. Then sweat with solder, and then 
cut off the ends not required. This method 
is frequently used, and is, if anything, 
slightly stronger than an ordinary spliced 
joint. This is not a surmise, but an actual 
practical fact, which has been proved. 
173 



HOW AN AEROPLANE IS BUILT 



STRETCHING CABLE. 
Before any cable is cut to the dead 
length required, it should be stretched up 
to its full load. This acts as a test of the 
strength of the cable, and prevents it from 
becoming slack after being placed in posi- 
tion in the aeroplane. Also, the stretching 
probably prevents one having to scrap the 
cable owing to its developing excessive 
length after being in use for a time. 

TESTING AND STRETCHING CABLES. 
The necessary material for the cable 
testing and stretching apparatus consists of 
two sound pieces of deal or pitch-pine, 16 
ft. long, 9 in. by 2 in. These will have to 
be planed all over, after which two pieces 
of 9 in. by 9 in. by 3 in. will be sandwiched 
between the two ends of these long pieces 
of timber so as to keep them 3 in. apart, 
on edge. When fastened to the legs they 
will stand on, they should be about 3 ft. 
6 in. above floor level. 

These 9 in. by 9 in. by 3 in. packing or 
distance pieces will be securely glued and 
bolted in their permanent position. After 
this, f-in. holes must be drilled through the 
centre of each piece of timber on each 
side-face, exactly opposite each other, 
about 9-in. centres, to allow of the tension- 
head of the apparatus being moved, and 
the length of the apparatus being adjusted 
to suit different lengths of cable. 

!74 



HOW AN AEROPLANE IS BUILT 



THE TENSION-HEAD. 

Having completed the apparatus so far, 
the next thing to do will be to construct the 
tension-head. This can consist of a piece 
of sound, well-seasoned ash, about 1 ft. 6 in. 
long, by 9 in. by 3 in. This will have a 
f-in. hole drilled through the 3 in. thick- 
ness of the piece, in the centre, and 4^ in. 
from one end, so that the f-in. bolt, which 
passes through the side of the 16-ft. tim- 
bers, can pass through this piece also and 
hold it in position. On the sides of this 
short piece of ash two chocks, each 9 in. 
long by 3^ in. by 2 in., will be glued and 
bolted. And further, through the edge of 
this piece of ash, which is 3 in. thick, will 
be drilled a f-in. hole. This is for the f-in. 
tension-bolt to pass through, to which the 
cable which has to be stretched is attached. 

At the other end of the 16-ft. timbers 
will be fixed a 10 to 1 bell crank-lever, or 
combination of levers. The short end will 
project upwards between the two 9 in. by 
2 in. timbers, and to this will be fixed a 
suitable swivel link to which to attach the 
cables. 

At the long end of the lever arrange- 
ments and fittings will be made for attach- 
ing a spring balance, capable of reading 
up to a load of at least 300 lbs. This will 
be used for the purpose of indicating the 

175 



HOW AN AEROPLANE IS BUILT 



amount of strain to which the cable is being 
strained. (See Fig. 30.) 

The many uses for testing purposes to 
which this machine can be put, and the 
valuable data obtained thereby, quickly 




CABLE TESTING OR STRETCHING MACHINE 

Fig. 30. 



repay its cost. The use of one of these 
machines is badly needed in most works 
using cables and ropes. It is easily made, 
and cannot get out of order. Also, accu- 
rate readings can be obtained by any intel- 
ligent person. 



CHAPTER XVII 



CASTLE NUTS AND THEIR MANUFACTURE. 

Regarding the use of nuts, it frequently 
happens that "castellated" nuts have to 
be used, and, assuming that supplies have 
run out, which occasionally happens, it 
may cause considerable delay in waiting 
for further supplies from the actual manu- 
facturers. Therefore, having described 
in the Tenth Instalment of this article the 
method generally adopted for making 
small bolts, it may be as well to add in this 
Instalment a method frequently adopted 
for cutting the slots of castellated nuts. 

A small or large plain milling machine 
will be utilised for this purpose, 

To the table of the machine attach a 
machine-vice, and in between the jaws lay 
a rectangular bar of mild steel which has 
been "shaped" all over. The length of 
the bar being not less than the length of 
the jaws, the size of this bar will depend 
on the size of the nuts to be castellated. 

This bar of steel may be a few hundredths 
of an inch less in width than the width 
across the corners of the nuts (see Fig. 31). 
This is for the nuts to rest on, to keep them 
up to the slitting-saw. 

For the purpose of holding, say, half a 

177- 

M 



HOW AN AEROPLANE IS BUILT 
dozen nuts in between the machine-vice 
jaws, in their correct position for slotting, 
we must prepare two pieces of angle steel 
with vertical Vee slots cut in each of them. 
These Vee slots are for the purpose of 
gripping the corners of the nuts firmly, 
whilst they are being castellated. 

Owing to these Vee slots being required 
in the angle steel pieces, it will necessitate 
them being made out of the solid bar, the 
angle for laying on the machine-vice jaws 




PACK IIM& 1 PIECE 



J IG FOR HOLDING NUT5 TO BE SLOTTED 

Fig. 31. 

being either milled, planed, or shaped out. 
As these two pieces of angle steel will be 
subject to considerable work, it will be as 
well to make them at least | in. thick all 
over, and case-harden them. 

THE USE OF THE JIG. 
Having made the above jig for castellat- 
ing the nuts, all that has to be done is to 
fill up the new angle jaws with as many 
i 7 8 



HOW AN AEROPLANE IS BUILT 



nuts as they have Vee slots in them and 
carefully see that each nut beds down 
equally on the packing-up strips under 
them. Tighten up the jaws firmly, fix the 
slitting-saw in the mandril, and adjust the 
height of the milling machine table, and 
thereby regulate the depth of the slitting- 
saw cut in the nuts. Start the machine and 
the cross-feed and lubricate the saw with 
the cutting compound. 

By this means half a dozen nuts can be 
quickly slotted across two flats of each of 
them. As soon as this operation and cut 
is finished, stop the milling machine, un- 
screw the machine-vice slightly, turn each 
nut round, and slot twice more, and the six 
nuts are done. By this means nuts are 
slotted or castelled quickly, cheaply, and 
accurately. 

HINGE BOLTS. 

The milling of small hinge bolts is a sub- 
ject which may be useful to consider, also 
the drilling of the pin-hole. 

The small hinge bolts having been turned 
out from the capstan lathes, and being 
made out of round bar, will at this stage of 
manufacture only have cylindrical heads, 
therefore it is necessary to prepare a jig 
to hold them in whilst the heads are 
squared on the sides and the tops formed 
to a radius (see Fig. 32). 

179 



HOW AN AEROPLANE IS BUILT 



MAKING A BOLT JIG. 

The jig may be formed in the following 
manner : — 

The pattern-maker will be instructed to 
make a plain, rectangular pattern with the 
ends flanged for bolting down onto the 
table of the milling machine. The length 
will be about 10 in., the width 4 in., and 
the thickness about 3-| in. (see Fig. 32). 



hinge 



BOLTS 



tf P 




MILLING JIG 

Fig. 32. 

Plane up the top and bottom surface of 
the castings, which will be cast-iron. Then 
mark out the longitudinal centre line of 
the casting on the top side. On this line 
space out, at about 1-in. centres, the holes 
into which will be placed the hinge bolts 
to be milled. Drill these holes right 
through the casting to the bottom. 

The next thing to do is to provide some 
means of fixing the bolts to be milled, 

180 



HOW AN AEROPLANE IS BUILT 
therefore a hole must be drilled through 
the centre of the side of the casting, at 
right-angles to the existing holes, at each 
one, in such a position that the circle of 
the fresh hole cuts the existing hole by 
about one-third of its diameter. Into these 
holes will be fitted plain bolts, with nearly 
one-third of their side filed off, so as to 
form a taper wedge against the bolt which 
is in the vertical hole to be milled. To 

HINGE BOLT > HARDENEP.BOSH 




DRILLING JIG 
Fig. 33. 

prevent the wedge bolt from turning round 
and causing trouble when other bolts are 
required to be inserted for milling, a 
feather is fitted to the wedge bolt and a 
slot is filed in this bolt hole to take it. 

METHOD OF USE. 
Having completed this jig, the method 
of working it will be to take, say, six bolts 

181 



HOW AN AEROPLANE IS BUILT 
and drop them in the vertical holes, mak- 
ing sure that they are right home. Then 
firmly tighten up the nut at the end of each 
wedge bolt, thus locking all the bolts to be 
milled in position. Fix the jig on the table 
of the milling machine with bolts, and then 
fix the milling cutters. Adjust the height 
of the table and proceed with the work. 

Having completed the milling of the 
heads of the hinge bolts, the next thing is 
the drilling of the pin-hole in them, and for 
this purpose a small drilling jig can easily 
be made (see Fig. 33). 

Having dealt with the construction of 
many metal parts necessary for the con- 
struction of aircraft, and possibly suffi- 
ciently to enable those new to the Industry 
to gain some insight, one may as well next 
deal with the finishing up of the various 
parts of the machine. 

These important component parts may 
be dealt with in the following order, 
namely, the centre-section plane, the top 
and bottom main planes and ailerons, the 
tail plane and elevators, the fin, and the 
rudder and fuselage. 



CHAPTER XVIII. 



COMPLETING THE CENTRE SECTION. 

The centre plane being of wood, it will 
be sent to the paint and varnishing depart- 
ment, where it will receive (subject to this 
system being adopted by the management) 
two coats of spirit-varnish all over, then 
the small riblets and rib-noses will be 
covered top and bottom sides by a strip 
of half-inch India tape, glued on, the total 
length of which will be about 2 ft. 3 in. for 
each length of tape. 

As soon as the glue is dry and set, the 
top and bottom edges of all parts forming 
the centre plane will receive one good 
coat of white dope-resisting paint, as will 
all fittings, tie rods, wiring plates, bolts and 
nuts. The centre plane will then be ready 
for inspection by the A.I.D. 

The same process applies to the main 
planes, tail planes, elevators, fins and rud- 
ders, with regard to the white dope-resist- 
ing coat of paint. Of course, spirit-varnish 
is not put on steel-tube constructions, which 
are only painted with the dope-resisting 
paint. 

COVERING. 

This work of painting having been care- 
fully completed, these parts will be sent to 
the covering shop. 

183 



HOW AN AEROPLANE IS BUILT 
The centre plane is the first member to 
be covered. During the time the covering 
department has been waiting for these 
various components to come along it has 
been busy cutting out and machining up 
the covers, and putting the small eyelets 
for laces into the covers of the fuselage and 
many other small jobs. 

A WORD OF WARNING. 

Here I pause to point out a word of 
warning. Before attempting to fit on the 
covers on the planes and stretch the covers 
taut and sew up, take care to see that the 
linen fabric is absolutely dry and well- 
aired. Unless you can be fully satisfied 
regarding this point, stop covering until 
you have taken the necessary steps to dry 
and air the fabric. 

The reason for this is that however little 
percentage of dampness or moisture the 
fabric may contain it will be contracted in 
area, and however tight it may be stretched 
and sewn on, it will relax and become 
quite slack on coming in contact with the 
warm, dry air of the dope room. It is 
fairly safe to say that no amount of doping 
will succeed in bringing up the tautness of 
the fabric as it is required for first-class 
wings, and the finished article will be a 
disappointment. 

PUTTING ON THE FABRIC. 
In covering the wings it is usual to put 
on the covers over the leading edge. 

i8 4 



HOW AN AEROPLANE IS BUILT 
Stretch the cover over the top and bottom 
of the ribs, then stretch the fabric to the 
trailing edge and tack down with a few 
fine gimp pins. Sometimes this is done 
with pins. The fabric should then be 
stretched lengthways and all seams straigh- 
tened from the front to the back. 

After which the two surplus ends of the 
fabric should be cut off, leaving only about 
half an inch of each end to turn in and 
make a seam. The sewing up of the seam 
may then be commenced. 




Fig. 34. 



The first stitch should be made by pass- 
ing the needle through the fabric from the 
inside, pulling it through and passing over 
the edge, then across the gap to the fabric 
on the top of the wing. Here the needle 
is again passed from the inside of the fabric 
to the outside, and the stitches both drawn 
together (see Fig. 34). This has the effect 
of neatly and tightly drawing together the 
ends of the fabric. 

STRINGING. 
The wing will now have to go through 
the process of " stringing." This consists 



HOW AN AEROPLANE IS BUILT 



of putting a loop of string over the fabric 
and round each rib, and knotting and 
carrying the end of the string about four 
inches farther on and repeating the same 
operation. This is done to each rib, on 
which there will be about eight or nine 
loops. 

This is for the purpose of attaching the 
fabric to the ribs, preventing the fabric 
ripping, and generally helping to distribute 
the load. The lines of string are after- 
wards covered with strips of fabric, with 
frayed edges, to give a neat, smooth and 
strong surface. 



CHAPTER XIX. 



DOPING, VARNISHING AND PIGMENTING 

The wing will now be ready for doping, 
and will be taken to the dope room. Be- 
fore commencing doping the temperature 
of the room must be at least about 70 deg. 
Fahrenheit. This temperature is demanded, 
not for the purpose of causing the con- 
tractor trouble and annoyance and the ex- 
pense of putting in and maintaining a heat- 
ing apparatus, but for the purpose of ob- 
taining satisfactory results with the dope 
employed, namely, good adhesion, a 
smooth surface, and what may possibly 
appeal to the contractor, rapid produc- 
tion. 

This remark specially applies to the coat 
of aeroplane varnish which is applied to 
the underside of the wings, as some makes 
of varnish will take seven to eight hours 
to dry and sometimes longer, and with a 
good temperature it is easy to save half an 
hour, which means a lot to the contractor 
whose space is limited, and thereby output 
is increased. 

DOPING WINGS. 
The wing which has to be doped can be 
laid on some trestles made a convenient 

is 7 



HOW AN AEROPLANE IS BUILT 
height, say about 2 ft. 9 in. On these will 
be laid or fixed pieces of wood about the 
same length as the spars, and the wing- 
spars will rest on these and nowhere else. 
Taking the weight, these will prevent the 
fabric from being strained, and possibly 
punctured. 

The dope will now be put into a can 
capable of holding, say, about a quart, and 
with a narrow slot in the top like a letter- 
box slit, through which to put the brush. 
A brush about 4 in. wide should be used 
to spread the dope. 

In putting on the dope it is necessary to 
put it on, and especially to spread it, 
quickly and evenly. Take plenty on the 
brush and work it evenly into the fabric 
backwards and forwards, and then finish 
by working it at right-angles to your last 
way of spreading. Then leave it to dry 
thoroughly before attempting the next 
operation. 

In doping it may be as well to go to the 
trouble of instructing the dope hands that 
to dope a wing properly they should not 
attempt to start on about half-a-dozen 
spots at once, they must start at one end 
and work first of all on a small patch of, 
say, 2 ft. by 1 ft. 6 in., and finish this 
before starting elsewhere. By this means 
it may be possible to get an equal quantity 
of dope all over the wing, and not patches 
of dope, as is frequently the case with 

1 88 



HOW AN AEROPLANE IS BUILT 
inexperienced hands, who do not know 
any better, and occasionally who don't 
think. Some are honest enough to tell you 
so, as I have frequently heard them say, 
" I don't think." I do appreciate their 
honesty, although it is a trifle annoying 
to those holding responsible positions. 

FRAYED FABRIC. 

Having completed the first coat of dope, 
the next thing to do is to obtain the frayed 
or " spaced " fabric from the stores. This 
is ordinary fabric of ordinary width, in 
which the threads called the "weft," 
namely those which run longitudinally in 
the fabric, are left out about every two 
inches for a width of about half an inch. 
This is cut into strips and laid on over the 
rib-stringing and well doped down, also 
strips are laid along the edges for the pur- 
pose of strengthening the fabric and pre- 
venting it from tearing. 

The method of attaching this frayed 
fabric is to dope the surface well and take 
a length with both hands. Lay it against 
the doped surface, or on it, and then rub it 
well down, either with the fingers or a 
piece of fabric. Then well dope over it 
with a brush. 

When this has well set, the final coats of 
dope may be applied. 

189 



HOW AN AEROPLANE IS BUILT 



IDENTIFICATION MARKS. 

The next thing to do is to set out the 
identification mark according to the in- 
structions and official measurements given. 
This is painted on by a painter with some 
experience in sign-writing or fine work. 

When this is dry the " khaki " pigment 
is put on the top of the wing. Generally 
two coats are necessary. This being dry, 
the wing is turned over and given the final 
coats of varnish and left to dry. 

When dry the wings, with the ailerons 
and the tail plane, the elevators, fin and 
rudder, which have been doped, will be 
taken to the finishing shop to have the 
external fittings attached. 



CHAPTER XX. 



THE FINISHED PARTS, STORES, AND THE 
ASSEMBLING SHOP. 

The wings, ailerons, tail plane, elevators, 
etc., having been received from the dope 
shop into the finished-part stores, they 
can here be examined and passed by the 
inspector. If suitable accommodation 
and room is available, the wings can be 
conveniently stored in racks in a horizontal 
position, the racks being double-sided, pre- 
ferably fixed with a walking space all 
round. 

In this way the top right and left-hand 
planes can be stored on one rack, and the 
bottom right and left-hand planes can be 
stored in another rack. Thus quite a large 
number of wings, elevators, or tail planes 
can be stored in a small space until re- 
quired in the erecting shop or for despatch. 

Similar racks are useful in the dope room 
to store planes when a large number are 
being pigmented or varnished, whilst they 
are drying. It is far preferable to keep the 
planes in racks instead of leaning them in 
piles against walls or partitions, where they 
are liable to be damaged by people's feet 
walking by, besides scratching the edges 
and distorting the wing, owing to it being 
improperly supported. 

191 



HOW AN AEROPLANE IS BUILT 



A PARTS ASSEMBLY SHOP. 

In all works an Assembling Shop 
situated conveniently near to the Erect- 
ing Shop should be provided. This 
shop we can assume for our pur- 
pose to be about 30 ft. square, with two 
narrow benches along the walls opposite 
to each other. About five pairs of trestles, 
with 3-in. by 2-in. rounded bearers, suffi- 
ciently long to support the whole length of 
the wing, should also be provided. 

In this shop, on the walls, a few small 
bins for holding the external fittings in can 
be fixed up, and if possible a small electric 
portable drill for drilling pin-holes. Into 
this shop all wings, elevators, ailerons, etc., 
can be brought to have their external fit- 
tings put onto them. To many managers 
this may seem a unnecessary sub-division 
of the erecting shop duties, but it will be 
found to save time, decrease wasted room 
in the erecting shop, specialise labour in 
their work, facilitate cost-keeping, expe- 
dite the erection of complete machines, 
lessen the labour and supervision of the 
erecting-shop foreman, centralise respon- 
sibility for perfect work, and generally 
speed up output. So it seems worth while. 

THE COMFORT OF WORKERS. 
Further, the bulk of the work can be 
done by one man, assisted by about six 

192 



HOW AN AEROPLANE IS BUILT 



intelligent girls, who, if they are at all suit- 
able for the work, easily pick it up in about 
a fortnight, especially if conditions for 
work are comfortable. There should be 
plenty of air, light, and reasonable warmth, 
which is as necessary for the planes, etc., 
as the workers. 

There are some people who say, " work, 
and keep yourself warm." This is possible 
if you are shifting and erecting heavy 
steelwork, digging a hole with a pick and 
shovel, or, better still in cold weather, fir- 
ing a marine boiler ; but aeroplane work 
does not happen to be similar to any of 
these blood-circulating occupations. In 
many cases it requires a certain amount of 
delicacy of touch and care and patience, 
none of which qualities contribute to 
warmth. 

Therefore, it is as well to give attention 
to the subjects of air, light, and warmth, 
as it is quite possible for a large shop full 
of workers, say a hundred, to spend 
twenty-five per cent, of their time in think- 
ing how cold it is. To estimate the cost of 
this occupation, ask them to book a quarter 
of an hour every hour to this on their time 
sheets, and then ask the Cost Office for the 
account at the end of the week. 

The wings, ailerons, tail planes, fins, 
rudders, etc., can be brought into this as- 
sembly shop to have their external fittings 
attached. The wings, for instance, require 
193 

N 



HOW AN AEROPLANE IS BUILT 
their lift plates and eyebolts put on and 
split-pinned, and the spar brackets or other 
hinges attached. In fact, an immense 
amount of incidental yet important work 
can be done here, thus saving a large 
amount of room required for complete ma- 
chines. 



CHAPTER XXI. 



ERECTING THE MACHINES. 

The complete erection of the aeroplane 
has now to be considered briefly. 

We can assume that the fuselage skeleton 
is complete ; this will be put on two trestles 
in the erecting shop, and the trestles should 
have some simple form of adjustable head, 
so that the height of the work on them can 
be varied. This is essential, especially in 
this instance, as the under-carriage has to 
be fitted onto the fuselage, and it is handy 
to be able to raise or lower the fuselage 
without having to look for a few pieces of 
loose wood. These do not invariably form 
a solid packing for the fuselage such as is 
required to enable the fuselage to be held 
in a horizontal position. 

ACCESSORIES IN THE ERECTING SHOP. 
The under-carriage having been at- 
tached to the fuselage and all the bolts put 
in and split-pinned up, the axle can be put 
into its position. The shock-absorbers can 
be then wound on and the aluminium 
streamline fairing attached. It will not be 
advisable to put on the wheels until the 
machine is practically finished, as the tyres 
deteriorate, the covers get dirty and 



HOW AN AEROPLANE IS BUILT 
frequently torn, and everybody makes 
footsteps of them. Therefore, a pair of 
small wooden Vee trestles should be made, 
into which the bearing-ends of the axle 
can rest. 

The axle, however, should be lashed 
firmly to the chassis-struts so as to prevent 
the load from coming on the shock- 
absorbers, as these being made of rubber 
will deteriorate and become stretched if 
the machine is left standing for a consider- 
able time, as sometimes occurs before final 
delivery. 

As a considerable amount of work will 
have to be done which involves the workers 
being about eighteen inches above the 
floor level, it would save a considerable 
amount of waste of time and litter of old 
boxes kicking about the shop if a few 6 to 
8ft. forms are made on which the workers 
can stand. 

PRELIMINARY FITTINGS. 

The next thing to do will be to fix the 
tank bearers and prepare for the reception 
of the tanks for the petrol and oil supply. 
As soon as these are fitted, it will be as well 
to put in the instrument board so that in- 
struments can be set out in their respective 
positions and screwed into their positions 
after any necessary cutting and fitting has 
been done. 

As soon as they are in position the Cop- 
ied 



HOW AN AEROPLANE IS BUILT 
persmiths should be detailed off to fit in 
the copper pipes and bends from the in- 
struments to the tanks, at the same time 
the installation of the controls can be com- 
menced, the rudder-bar being fixed in 
position, and the " joy-stick," or control 
pillar, for working the aileron and elevator 
controls. 

Having put these in, the streamline fair- 
ing on the fuselage can be fitted. In some 
machines this is an independent unit in one 
piece, in others it is built up on the fuselage 
in skeleton form and covered with fabric, 
which is afterwards doped and varnished. 
Also, the fuselage will be covered round 
with fabric, which is stretched on and 
tacked to the longerons, and the tacks 
finished off or covered over with a small 
half-round beading. 

FIXING THE TAIL. 
The tail plane can next be attached to 
the fuselage, but before being finally fixed 
in position it must be tested to see that it 
is fairly and squarely at right-angles to the 
longitudinal centre-line of the machine. 
This can be done with long trammel points 
or a steel tape, and measuring from the 
left and right-hand tips of the tail plane to 
a fixed point on the centre-line of the 
fuselage ; this must be dead right and an 
equal measurement on either side. Differ- 
ences, however small, cannot be per- 
197 



HOW AN AEROPLANE IS BUILT 
mitted, and all necessary alterations must 
be made until the dimensions are accurate. 

ENGINE FITTING. 

For the moment, as most work is being 
done at the tail-end of the machine, it may 
be considered a suitable time to lift the 
engine into position, but before lifting it in 
it is necessary to secure the tail of the 
machine in some way to the floor, either 
with ropes fastened to temporary cleats 
screwed to the floor, or some heavy weight. 
Unless this is done the machine will tilt up 
when the engine is installed, as the weight 
of the engine is considerable. 

It is not advisable to expect the engine 
erectors, either with or without help, to lift 
the engine into position. The lifting should 
be done with a half-ton worm-geared chain 
tackle, and some good, reliable 1^-in. 
rope, and a couple of stiff bird-mouthed 
bits of wood to put between the rope slings 
to prevent them from bending or breaking 
various parts of the engine or chafing or 
cutting themselves. Also, incidentally, it 
is advisable to attach the tackle to some- 
thing which is capable of standing at least 
double the weight of the engine. Gas pipes 
and electric conduits, or coat-hooks, 
should be considered out of bounds, and 
may be neglected as anchorage for the lift- 
ing tackle. 

Having installed the engine in position, 
198 



HOW AN AER OPLANE IS B UILT 
it is best to put an adjustable trestle under- 
neath the nose of the fuselage in case the 
ropes which hold the tail end of the ma- 
chine down give way. This incident has 
occurred before now, with disastrous re- 
sults to the engine. 

It will then be necessary to check the 
engine to see that it is in line with the line 
of flight, and with the fuselage we have 
constructed. The line of flight will pro- 
bably be that of the top longerons. It is 
from this line we must work, as it is our 
only base from which to start. 

The engine which is being installed in 
this case is of a radial type, and will, there- 
fore, be fastened to the front and the back 
engine-plates, which are attached to the 
fuselage. Therefore, we must satisfy our- 
selves that the front engine-plate is truly 
at right-angles with the line of the top 
longerons. Also, the plate must be tested 
to make sure that it is transversely at right- 
angles with the centre-line of the whole 
fuselage. Unless this is done, the engine 
and propeller will always have a tendency 
to look either to the left or the right, ac- 
cording to whichever side the engine-plate 
inclines. 

The reason for this demand for accuracy 
is that the aeroplane is designed to fly 
normally in a dead straight line, and it will 
not do this if the engine is not fixed 
squarely and truly in the fuselage. 

i 99 



HOW AN AEROPLANE IS BUILT 



PETROL CONNECTIONS. 
The installation and the coupling up of 
the petrol and oil pipes must next be taken 
in hand. Before any pipe of any descrip- 
tion is finally coupled up in its position, 
the pipe should be thoroughly tested, pre- 
ferably under steam or air pressure, for 
strength and leaks, and also to make abso- 
lutely sure that there are no obstructions of 
any kind inside its whole length ; this pre- 
caution is most necessary and cannot be 
too strongly impressed on all concerned ; 
in fact, I consider that in view of the im- 
portance of this matter it should come 
under the Inspection Department (A.I.D.). 

The bending and the adjusting of pipes 
should only be done by workers who are 
skilled in this class of work, as dents and 
kinks of any kind should not be tolerated 
in the smallest degree, as it causes ineffi- 
ciency in the whole system of piping. Also 
all spelter should be carefully cleaned off 
all brazed joints and the pipes generally 
should be finished off in a high-class work- 
manlike manner. Any deviation from this 
standard is undesirable. 

The revolution counter, and the shaft 
for driving it, will next be required to be 
fitted and coupled up. 

During the time that the pipes were be- 
ing tried and fitted into position, the cowl- 
ing over the engine should have been in the 

200 



HOW AN AEROPLANE IS BUILT 
hands of the coppersmiths and panel 
beaters, and can now be fitted on. 

FITTING THE COWL. 

The engine cowl is generally made of 
about 22-gauge aluminium sheet, and is 
either pressed out, spun or beaten to shape. 

In measuring up for the quantity of metal 
sheet required to make a cowl, it is just as 
well to measure round the outside circum- 
ference of the cowl on a sectional eleva- 
tion. It should be borne in mind that the 
metal has to be pressed or hammered to 
this shape without distorting or thinning, 
although, of course, this does take place in 
a small degree, but it is not desired to a 
measurable extent. 

Before proceeding with the final fixing 
of the cowling and aluminium fairing gene- 
rally, it will be as well to fix the centre 
plane struts into their sockets on the top 
longeron of the fuselage, attach the centre 
plane to same, and put the bracing wires 
into position. This work requires the tak- 
ing of careful measurements, and the accu- 
rate adjustment of the fork-ends, so that 
an equal tension on each strut and bracing 
wire will be assured. Excessive tension is 
not required, as this only puts additional 
work on to the struts and fittings, and they 
are only designed for a certain load, which 
it is not desirable to exceed. When put- 
ting in the bracing wires, the insertion of 

201 



HOW AN AEROPLANE IS BUILT 
the split-pins in bolts should be left over, 
in case any alteration has to be made in 
the tension or position of any bracing or 
fitting or bolt. 

ASSEMBLING THE MAIN PLANES. 

The assembling of the main planes can 
be done in two ways. Firstly, by attaching 
one, say, right-hand or left-hand top wing 
first, using a trestle to support it, and at- 
taching the bottom wing on the same side 
afterwards, supporting this also on the 
trestle, until the interplane struts and lift 
wires are put in and adjusted to both wings. 

The alternative method is to stand both 
wings on their leading edges and then put 
the interplane struts into their respective 
positions, together with the bracing wires, 
and tighten up the whole lot just sufficiently 
to hold them together. Then the wings can 
be carried by the erectors to the machine 
and attached as a whole with the aid of a 
couple of pairs of tall steps. 

With reference to the above methods, 
there are advantages and disadvantages in 
them both, and it may be as well to give 
them consideration, to save waste of time 
and difficulty to those who have not had 
the experience of erecting wings on 
finished machines. 

As regards the first method, it can be 
recommended for the use of erecting shops 
where there is a lack of skilled men used to 

2Q2 



HOW AN AEROPLANE IS BUILT 
handling aeroplane wings ; secondly, it 
enables the erectors in the case of a new 
machine to set the wings up truly to the 
correct dihedral angle and angle of inci- 
dence at the same time, and to measure up 
the correct lengths for the bracing wires 
after the struts have been tried up and 
fitted to their permanent positions. 

WIRING LENGTHS. 

With regard to the last reason, of course, 
the mathematician will naturally come 
along and say that it is possible accurately 
to calculate the length of any side of a 
triangle, and that, as he is able to do this, 
the practical advantage which I have set 
forth is of no use, and need not be taken 
into account. I quite agree that his state- 
ments are perfectly correct, up to a point, 
and the point is, that the mathematical 
calculations do not tell one what effect the 
tightening of the bracing wires will have on 
the structure as a whole, or how much one 
bay will contract at the expense of another 
expanding, and because the mathematician 
has calculated to five places of decimals 
that a lift wire will be, say, 7.61500 ft. long, 
it most probably happens, when the ma- 
chine comes into the hands of the skilled 
erector who is responsible for tuning up 
the machine for her test flight, that the 
required length of the lift wire will be found 
to be, say, 7.54 ft. long, the loss of 0.075 in. 
203 



HOW AN AEROPLANE IS BUILT 
being due to the various struts bedding 
together under the strain and tension re- 
quired in a machine tuned up for flight. 

These remarks, therefore, emphasise the 
necessity for allowing an ample margin for 
adjustment in wires. Also, screw threads 
should not be too short, and under no 
circumstances should streamline wires, 
which are exceedingly difficult to get at 
the present time, be cut by irresponsible 
workers, without authority. (Fig. 35.) 
a <amt» e 




STREAM LINE WIR£ WITH FORK JOINT 

Fig. 35. 



The disadvantages of erecting wings 
separately is that it entails more trouble 
in having to have high pairs of steps for 
the men to get up to the top wing to fix up 
the struts and attach the bracing wires, and 
it is sometimes awkward to drill split-pin 
holes when perched upon the top of a pair 
of steps about 10 ft. high. Also, there is 
the expense of the trestles. 

With regard to the second system : this 
method works well in the hands of experi- 
enced erectors, either in the works or out 
in the hangar, when erecting a machine 

which has just arrived from the makers at 

204 



HOW AN AEROPLANE IS BUILT 



the flying ground, as it saves time and 
trouble in having trestles and long pairs of 
steps and planks, and all split-pins can be 
fitted on the ground. The disadvantages 
are, that this method is only suitable for 
the erection of wings onto machines which 
have been previously assembled, as it does 
not enable accurate dimensions of bracing 
wires to be taken. 

MAKING A SHOP PROTRACTOR. 

The wings having been erected on the 
machine, the first thing to do will be to test 
the dihedral angle and the angle of inci- 
dence. For checking the dihedral angle, 
we shall require a protractor. However, 
a protractor similar to those used in the 
drawing office will not do, as it would not 
have sufficient length of base to give the 
correct general angle of the surface of the 
wings, nor is there any means of indicating 
what the angle is should one be used, so we 
must make what will be called a " shop 
protractor." 

For this purpose we will obtain a piece 
of mahogany or beech, 6 ft. long by about 
4 in. wide, by -J- in. thick. We will mark 
off the centre of this piece of wood, and, 
with a square, cut or mark a fine line across 
it. At 2 \ in. either side of this centre line 
mark points, and then cut half the piece 
of wood away and halve another piece of 
wood into it, at right-angles. This piece 

205 



HOW AN AEROPLANE IS BUILT 

of wood will be 5 in. wide by about 12 in. 
long. 

Onto this piece of wood, when it is fixed, 
continue the fine line already marked on 
the long piece right across. This line repre- 
sents the zero line of the pointer, which 
will be hung from a centre about \ in. from 
the base 

The next thing to do is to drill a \ in. 
hole through this centre, in the piece of 
wood. Then get two pieces of 12-gauge 
aluminium or brass, about 1 in. square, 
each with a \ in. hole drilled through the 
centre, and a hole at each corner big 
enough to take a \ in. by 2 gauge brass 
screw. Next obtain a \ in. bolt or metal 
thread and bolt the plates on to the piece 
of wood, each side. Then place the metal 
plates squarely in position and screw them 
on. 

These plates will form the bearings of 
the small \ in. pin to which is attached the 
pointer. The pointer should be similar in 
design to a large watch-hand, about 10 in. 
long, of fairly heavy design at the sharp 
pointer end, so that the weight of it will 
always cause it to hang in a perpendicular 
position. 

Before bolting on the pointer, take a 
large pair of finely-pointed dividers and 
scribe a segment of a circle on the side of 
the long piece of wood. On this line will 
be laid a piece of aluminium, about \\ in. 

206 



HOW AN AEROPLANE IS BUILT 



wide, and equal in length to about 1 / 6th 
of the circumference of a 10-in. circle, this 
being screwed to the piece of wood which 
forms the protractor. 

On this will be marked, in the centre 
with a fine pointed scriber, the zero line of 
the pointer. This zero line will be obtained 
by placing the protractor on the surface of 
anything handy in the shop, which has 
been checked with a spirit level and is 
known to be truly level, on two packing 
blocks of equal thickness. 

Then set out in \ degrees about 5 degrees 
either side of the centre line carefully, and 
check these lines, indicating the degrees 
with a level protractor. 

Having constructed the protractor, it 
will be as well to give it two or three coats 
of spirit-varnish to help to prevent it from 
warping, and then it may be considered 
ready for use. 



CHAPTER XXII. 



CHECKING THE ANGLES OF THE WINGS. 

To check the dihedral angle of the wings 
of an aeroplane, the first thing to do is to 
consult the plans showing the general 
arrangement of the machine, or some other 
competent authority if this information is 
not available on the drawings. 

Having obtained the drawings on which, 
we will assume, is the necessary informa- 
tion, the first thing to do is to ascertain 
where the line of flight traverses the body 
of the machine. In our case, we will 
assume that the top surface of the longe- 
rons of the fuselage are parallel to the line 
of flight. 

This being the case, our work is fairly 
easy, because we have a ready-made base 
line to work from. But we must not accept 
this without first checking it, in case any 
discrepancies exist. Therefore, the longe- 
rons must be tested with straight-edges, 
each about 3 ft. long, placed at intervals 
on the top of the longerons and sighted 
through. 

This operation will satisfy us that the 
fuselage is not twisted, and further, that the 
top surface of the longerons is straight and 
true. 

208 



HOW AN AEROPLANE IS BUILT 




HOW AN AEROPLANE IS BUILT 
Having satisfied ourselves on this point, 
the next thing to do is to level up accu- 
rately the top surface of the longerons, 
both longitudinally and transversely. This 
may mean packing up or lowering the tail 
of the machine, and then securing it firmly 
in this position with weights or any other 
available or suitable means; further, the 
machine should be supported direct, and 
brought level laterally, by putting packing- 
pieces under the ends of the chassis struts. 
Don't level up by putting packing under 
the tyres — which ought not to be fitted until 
later — for a tyre may deflate after the level- 
ling is done, and so throw all our levels 
out. And don't pack up the axle, because 
the lashing of the axle to the chassis struts 
may give a bit and upset our levelling. 

GETTING TO WORK. 

Having done this, we can commence to 
check the angles of the top main planes, 
or wings. For this purpose we shall re- 
quire a pair of high steps to enable the fore- 
man erector to place the protractor on the 
underside of the front part of the wing, 
preferably on the line of the bottom sur- 
face of the front spar ; we may then expect 
to read any angle on the protractor between 
deg. and 6 deg., this being the extreme 
dihedral angle which is likely to be wanted. 

We will assume that the design of the 
machine calls for an angle of 3^ deg., but 



HOW AN AEROPLANE IS BUILT 




211 



HOW AN AEROPLANE IS BUILT 
the angle of the wings, as erected, is only 
2 deg. Adjustments must now be made. 

FUNCTIONS OF BRACING WIRES. 

Before being able to make these adjust- 
ments we must consider how to do so. For 
this reason we must study the functions of 
the bracing wires, namely, the lift wires, 
the landing wires, and the incidence wires. 
The lift wires start from the fuselage and 
take an upward and outward course, being 
attached to the underside of the top main 
plane by the lift plates. These wires may 
be termed the Inner Lift Wires, because 
they are in the inner bay, formed by the 
centre plane struts and the inner struts. 

The Outer Bay Lift Wires are attached 
to the bottom of the inner bay struts, and 
run upward and outward, being attached 
to the lift plate at the junction underside 
of the top main plane with the outer struts. 

The Outer Lift Wires are attached to 
the plates at the foot of the outer struts, 
and these also take an upward and out- 
ward course, being attached to the under- 
side of the extension or overhang of the 
top main plane near the tip, though in some 
machines, on which the overhang of the 
upper plane is short, there are none of 
these wires, the lift being taken by the spar 
itself on the cantilever principle. 

Owing to the direction of attachment of 
these wires, it can easily be seen that when 



HOW AN AEROPLANE IS BUILT 
the machine commences to fly, and the top 
main planes commence to lift, that the 
effort will be transmitted through these 
wires unless they fail, or the bottom wing 
collapses. 

These Lift Wires are sometimes called 
Flying Wires and sometimes Load Wires. 

LANDING WIRES. 

The Landing Wires must next be con- 
sidered. These wires run in exactly the 
opposite direction, as they start from the 
wiring plates on the underside of the centre 
main plane, on the top of the centre plane 
struts, and take a downward course, being 
attached to the lift plates at the bottom of 
the inner bay struts. The Outer Bay Land- 
ing Wires start from the wiring plates at 
the top of the inner bay strut and are at- 
tached to wiring plate at the bottom of the 
outer struts on the top of the lower wing. 
These wires take the strain and load of the 
wings when landing, or the whole load of 
the machine when upside down, and by 
their direction transmit the whole load to 
the centre plane struts. 

These Landing Wires are sometimes 
called Anti-Load, or Anti-Lift, or Anti- 
Flying Wires, but Landing Wire is the 
most convenient and generally used term. 

INCIDENCE WIRES. 
The Incidence Wires as used, form a 

diagonal bracing fore and aft, between 

213 



HOW AN AEROPLA NE IS BUILT 
the interplane struts, and according to the 
amount of tension and the length of each 
wire, control the angle of incidence, or 
angle of attack, of the wings. 

TRUEING UP. 

Having briefly described the principal 
wires which go to form the bracing of a 
machine, we can now revert to the subject 
of trueing up the machine and checking the 
dihedral angle and bracing up the wings 
to the desired angle. 

Having erected the wings on the ma- 
chine complete, and tested the angle with 
the protractor, we find this is only 2 deg. 
instead of 3£ deg. This shows that the 
wings require lifting at the tips, so we must 
proceed to lift them with the wires, which 
are all more or less slack, not having been 
tightened up, as required finally for flight. 

The first thing to . do will be to slack 
off the Lift Wires a trifle, and then in- 
crease the tension of the landing wires to 
bring the wings upwards, starting with the 
inner bay landing wires attached to the 
tops of the centre plane struts and finishing 
up with the outer landing wires. Only a 
slight alteration in the tension may be ne- 
cessary, this being obtained with a few 
turns of the barrel of the strainer, or 
" turnbuckle," as it is called officially, or 
with a few turns of the barrel of the stream- 
line wires, whichever are used. 

ar 4 



HOW AN AEROPLANE IS BUILT 
The lift wires may then again require at- 
tention, for tightening up the landing wires 
may possibly have tightened them up too 
much, owing to the consequent slight de- 
formation of the parallelogram which is 
formed by the vertical struts on each side 
and the top and bottom spars above and 
below. The lift wires will be slacked off to 
the required tension by adjusting the turn- 
buckles to suit. 

Having done this to both the back and 
front spar, it will be as well to try the 
planes again with the shop protractor, and 
it is possible that with luck the right 
dihedral angle may have been obtained. 
If not, it is necessary to keep on doing it 
till the angle is correct. 

THE ANGLE OF INCIDENCE AND THE 
CHECKING OF IT. 

We must now turn our attention to the 
angle of incidence, this being checked by 
placing the straight edge or base of the 
protractor on the under side of the wing, 
one end of the protractor being on the 
trailing edge and the other on the leading 
edge, and observing the angle indicated. 
If the angle is too flat, then the leading 
edge wants raising. 

This is done by tightening the incidence 
wires which are attached to the top of the 
rear struts and run to the bottom of the 
front interplane struts ; having previously 
215 



HOW AN AEROPLANE IS BUILT 
slackened the incidence wires from the 
bottom of the rear struts to the top of the 
front struts. This has the effect of lift- 
ing the leading edge of the wing. The 
opposite incidence wires from the top of 
the front struts to the bottom of the rear 
struts must be slacked off to match. 

This being done, the angle of incidence 
should be again tried with the protractor 
as close as possible under the centres of 
the struts, and midway in between as well. 
If the angle of incidence is now found to 
be correct, then the erection of the wings 
may be considered complete, with the ex- 
ception of the controls. 

The ailerons must now be assembled in 
their places on the planes if this has not 
been already done when assembling the 
wings, as it should have been. And the 
aileron control wires should be fitted. 



2.6 



CHAPTER XXIII. 



ATTACHING AUXILIARY SURFACES. 
MOUNTING THE TAIL UNIT. 

The tail plane can now be fastened onto 
the end of the fuselage. As this is of a 
fixed position design, it simply means that 
the attachment bolts have to be put in and 
the nuts screwed up and split-pinned, the 
whole being attached to the metal attach- 
ment plates provided for it. 

The small bracing wires from the tail 
plane spars to the fuselage must also be 
attached. These, of course, are for the 
purpose of staying and bracing the tail 
plane and preventing it from twisting in the 
air when flying. 

THE FIN. 

The fin will have to be placed in its 
position on the top of the tail plane and 
bolted on, and the stay wire attached. The 
fin being made of steel tubing, as previously 
described, it may hardly be necessary to 
mention that the rear end of the fin is 
formed with a stout steel tube, onto which 
are attached the hinge fittings for the rud- 
der. 

In some machines, however, the rudder- 
post is a separate steel tubular post, fixed 

217 



HOW AN AEROPLANE IS BUILT 
to the stern-post of the fuselage, and the 
rear edge of the fin is attached to the front 
side of it, while the rudder is hinged to the 
rear of it. 

THE RUDDER AND ELEVATOR. 

The rudder will now be the next thing to 
attach, and it is at this stage and in other 
similar stages, that accuracy of work and 
the necessity for care in assembling hinge 
fittings will come forward. Owing to the 
fine limits of deviation allowed from the 
fixed measurements of hinges, any slight 
error will lead to scrapping the whole job, 
with consequent waste of time and labour 
and material. 

The rudder is attached to the steel tube 
by means of the small hinge fittings, which 
in this case are of the usual male and 
female design, with a small pin passing 
through both portions to keep them to- 
gether. The pins are kept in their places 
in the hinge fittings by means of a washer 
and small split-pin. 

The elevator-flaps will be similarly at- 
tached to the rear edge of the fixed tail 
plane. 

WHAT HAS BEEN DONE. 
We have now erected all the principal 
parts of the machine. To the front of the 
Fuselage are attached the Upper and 
Lower Main Planes, with their Ailerons, 

a-tS 



HOW AN AEROPLANE IS BUILT 
and the Centre Section Plane. At the tail 
end there is the Tail Plane, to which are 
attached the Elevators. And on the top of 
the fuselage at the tail end is the Fin, to 
which is attached the Rudder. 



CHAPTER XXIV. 



FINAL CHECKING. 

Before proceeding with the fitting up of 
the control cables and other work, we must 
accurately test the leading edges of the 
wings to see that they are correctly in line, 
and also that they are at right angles to the 
centre line of the fuselage, otherwise the 
flying of the machine will be affected ; also 
the tail plane, fin, and rudder must be 
checked. 

We will proceed first to check the lead- 
ing edge of the Lower Main Planes, be- 
cause it is more convenient to do so than 
to get up to the leading edge of the Top 
Main Planes. 

For the purpose of ascertaining that the 
leading edges of the Lower Planes are 
accurately in line with each other we will 
suspend three plumb-bobs from each lead- 
ing edge. Then we will strain a line across 
all the six plumb-lines, starting from the 
left plumb-line and finishing at the extreme 
right-hand plumb-line. 

It follows that, if the left-hand plumb- 
line is suspended from the tip of the left- 
hand lower plane, and if there are on this 
plane one plumb-line in the middle and one 
close up to the fuselage, and if there are a 



HOW AN AEROPLANE IS BUI LT 
similar lot suspended from the right-hand 
lower plane, and if a line is stretched across 
all of them, starting from the left and end- 
ing at the extreme right-hand one, and if 
the whole of the leading edge is straight, 
the line which is strained across will lightly 
touch all these plumb-lines and thereby 
prove that the planes have their leading 
edges in a continuous straight line. This 
is most important. 

SQUARING THE PLANES. 

So far we have only proved that the lead- 
ing edges are in a continuous straight line. 
What we now have to do is to prove accu- 
rately that this straight line is dead at right 
angles to the centre line through the axis 
of the engine and fuselage. 

We must therefore drop a plumb-line 
from the exact centre of the air-screw boss 
and drop another plumb-line accurately 
true with the centre of the rudder post. 
Then we must get two trestles or some 
objects having sufficient weight in them- 
selves to allow a line to be tied to each and 
strained taut. This line must reach from 
the plumb-line of the screw boss to the line 
suspended from the rudder post. As this 
line reaches from end to end of the 
machine, it naturally will cut the line repre- 
senting the leading edge of the lower main 
planes. 

Having got these lines set out and cut- 

221 



HOW AN AEROPLANE IS BUILT 
ting each other, the next thing to do is to 
find out if the line along the leading edge 
of the planes is at right angles to the line 
from end to end of the machine. This 
will be done with a large set-square. 

CHECKING THE UPPER PLANES. 

Having done this necessary checking, 
and having found that the Lower Planes 
are correct, we can start to check the 
Upper Main Planes. In checking the 
Upper Main Planes to see if their leading 
edge is parallel with the Lower Main 
Planes we must bear in mind that the 
Upper Planes have a forward stagger of 
six inches. Therefore, when the plumb- 
line is dropped down over the edge of the 
Upper Main Plane near the root of the 
wing, namely, at the inner end where it 
joins the Centre Section Plane, we shall 
find that the plumb-line, if the wings are 
correct, is six inches in front of the leading 
edge of the Lower Main Plane. 

WHERE CARELESSNESS IS DISCOVERED. 

This is as required ; that is to say, if the 
wings are correct. We will hope they are, 
because, otherwise, it will entail some ex- 
pensive alterations, not in material, but in 
the time taken, to say nothing of the annoy- 
ance. It is at this point that inaccurate 
work and measurements tell, and those 

222 



HOW AN AEROPLANE IS BUILT 

who have scamped their work are found 
out, as the accuracy of the erected wings 
is vital to the machine. 

It will be as well to leave the two lines 
strained taut, namely, the line representing 
the centre line of the fuselage and engine, 
and the line representing the leading edges, 
as from these lines we can check the square- 
ness and truth of the tail plane, which will 
next have to be dealt with. 

In checking the tail plane we can do this 
two ways ; we can measure with a steel tape 
from a marked and fixed point near the tip 
of the tail plane on the leading edge, each 
side of the machine, to a fixed point on 
the leading edge of each of the lower main 
planes. (Take care to use the brass ring 
of the tape, and include it as part of the 
measure, a point many men fail to note, 
and are consequently astounded at the 
imaginary error they find in the measure- 
ment, due to their own lack of knowledge 
in measuring with steel tapes.) 
_ This distance should be equal on either 
side of the machine. If it is not, then some 
adjustment must be made with the fittings 
of the tail plane, to enable the measure- 
ments to be corrected and equal. 

These measurements will have to be 
taken again as soon as the necessary ad- 
justments are made and the distances 
equalled and corrected. 

223 



HOW AN AEROPLANE IS BUILT 



TRUEING THE RUDDER. 

Whilst all this is being done, we must 
ascertain that the rudder is in a truly ver- 
tical position. It is hardly necessary to 
point out that before checking the rudder 
to ascertain if it is in a vertical position it 
will be necessary to satisfy oneself that the 
fuselage has not been moved or shifted 
from its horizontal position, both longitu- 
dinally and transversely, otherwise the 
check will be of no use. 

To check the rudder we may use a 
plumb-line and plumb-bob, which can be 
held close up to the trailing end of the 
rudder, and then the inspector, or erector, 
can sight across this line to the edge of the 
rudder. If the rudder is out of truth then 
the edge of the rudder will not coincide 
with the plumb-line. This is not probable 
unless some bad work in the fittings has 
passed unnoticed. 



224 



CHAPTER XXV. 



ODD JOBS AND GENERAL EXAMINATION. 

Having checked the position of the lead- 
ing edges of all the planes on the machine, 
relative to their being at right-angles to 
the centre line of the fuselage of the 
machine, we can now proceed to attach 
the cable controls. 

Other men can be detailed to lock up 
all the bracing wires, with the lock-nuts, 
and put in all split-pins, and spread the 
ends of same. If circular steel wire and 
strainers are used, then the barrels must be 
locked with soft iron wire, fastened round 
the upper portion of the fork-end and 
passed through the barrel of the strainer, 
and the end again made fast to the wiring 
plate or eye-end of the strainer, to prevent 
the barrel from turning round owing to the 
vibration of the wires. 

ATTACHING CONTROL CABLES. 
The attaching of the control cables 
should be only done by experienced erec- 
tors, namely, men who are thorough and 
conscientious in their work, and know what 
are the functions and uses of the ailerons, 
elevators and rudder. 

Before putting in any of the cables, etc., 
225 



HO W A N AER OPLAN E IS BUILT 
they must be very carefully examined for 
faults of any kind, even though they may 
have been previously supposed to have 
been examined and passed. The responsi- 
bility must rest with the erector who puts 
them in. 

AILERON CONTROLS. 

The first cables to put in will be the aile- 
ron controls. These will be attached to 
the control wheel, or control pillar, which 
works them. 

In putting in the cables excessive taut- 
ness is not desirable, as it only puts un- 
necessary strain on all the pins, fork and 
eye-ends, cable joints, cables, and the 
pulleys and fittings holding them, and 
lastly, on the bolts holding these fittings to 
the spars and levers. This in due course 
will cause excessive resistance to move- 
ments, and will possibly cause some por- 
tion to fracture or bend. 

Controls must be absolutely sensitive, 
and the slightest movement of the control 
wheel or lever should correspondingly be 
transmitted to the ailerons. To produce 
this simultaneous movement there must be 
perfect and equal tension in the left and 
right-hand control cables without excessive 
tautness, otherwise the machine is going to 
be hard to control, and very fatiguing to 
the pilot. These faults are most undesir- 
able, and if allowed to exist may have bad 
and far-reaching results. 

226 



HOW AN AEROPLA NE IS BUILT 
All controls should respond to any 
applied force with smoothness and ease of 
movement right up to the extreme limits of 
movement possible, and any tightness or 
stiffness at any part of the movement 
should be most carefully traced from the 
lever, along the cables to the ailerons, 
elevators, or rudder, according to which- 
ever, unit is being tested, and the fault 
should be removed without fail. 

ANGLE OF MOVEMENT. 

The angle of movement, both up and 
down, of the ailerons and elevators must 
be equal, and also be equal on both sides 
of the machine, one with the other. This 
angle of movement required will be 
obtained from the drawings, and must be 
carefully measured. The inspector must 
satisfy himself that the maximum angle of 
movement called for is obtained. This 
remark applies equally to the ailerons, 
elevators, and rudder. 

In fixing up the control cables it is just 
as well, for the first trial, to test the control 
of either the ailerons, the elevators, or 
rudder, independently, so that in the event 
of any stiffness of movement existing it 
may be quickly located and remedied. 

Having fitted up the control cables inde- 
pendently from the ailerons, the elevators, 
and the rudder, they should be all coupled 
up together and the whole control tested, 
' 227 



HOW AN AE ROPLA NE IS BUILT 
and if found to give the maximum angles of 
movement required with smoothness of 
working, the controls may be considered 
complete. 

TRACKING AIRSCREWS. 

The airscrew can now be put onto the 
shaft, with its locking nut and locking 
washers, after which the screw should be 
tracked. This consists in making sure 
that the axis of each blade travels in pre- 
cisely the same path as all the others. If 
it does not, then it means that the airscrew 
boss is not bedded correctly at right-angles 
to the shaft. 

The work of setting this right must not 
be put in the hands of any except the most 
experienced erectors, otherwise the fault 
will easily be made considerably worse, or 
the airscrew scrapped. It is possible that 
the whole of the necessary alteration may 
be made by slackening out the bolts on the 
side opposite to the airscrew blade which 
requires bringing into the true track, and 
tightening up the side affected, or vice 
versa, according to the direction required. 

The limits allowable for screw blades to 
be out of the true track may be assumed to 
be, at the most, -§• in. Any further amount 
will require to receive special sanction, 
and should be reported to the head of the 
department concerned. Possibly it may 
be necessary to take the airscrew off the 

228 



HOW AN AEROPLANE IS BUILT 
shaft, remove the boss from the screw, 
and check the sinking. It is then worth 
while to make sure that there is no rough- 
ness or raggedness at the edges of the bolt 
holes, for this would be quite sufficient to 
be the cause of the trouble. 

GENERAL EXAMINATION. 
The next thing to do now is systemati- 
cally to examine the whole machine and 
make sure that all wiring plates are in the 
same line as the cables attached to them, 
otherwise, when the flying strain comes on 
them, they will flatten out, or a fork-end 
may snap, possibly with disastrous conse- 
quences. 

Also, it is necessary to see that the angle 
of the bend of wiring lugs commences close 
up at the head of the attachment bolt, and 
also that one of the flat faces of the bolt- 
head is square to the bent lug. These de- 
tails, though of no particular interest pos- 
sibly to the lay mind, or inexperienced 
erector, are quickly noticed by the inspec- 
tors or pilots. Such errors are certain to 
cause considerable dissatisfaction, and will 
have to be eliminated. For this reason 
only men who have had experience in 
erecting machines ready for flight should 
be put on this inspection work, as their 
training and past experience in these mat- 
ters enables them to know exactly where 
to look for faults, and when found, to know 



HOW AN AEROP LANE IS BUILT 
if they can pass the work or not. And if 
they will not pass, as they should not, they 
know what is the most suitable way of deal- 
ing with such faults. 

The next thing to examine will be the 
cable-ends and strainers, or fork-ends, and 
see that all split-pins are properly put in. 
There are a considerable number of 
people, both men and women, whose duty 
at times is to put split-pins into position, 
who have not the remotest idea of how 
they should be put in, and the ghastly 
samples of this simple operation which are 
frequently met with certainly call for com- 
ment of a forcible or even lurid character. 

SPLIT-PINS. 

A split-pin consists of a length of half- 
round soft iron wire bent double, with a 
loop in the middle of the length, and the 
ends when closed together meeting evenly 
and forming a round wire, to all intents 
and purposes. 

The split-pin thus described is generally 
used to pass through two slots of a castel- 
lated nut and the centre of the bolt, not 
less than 1/16 in. from the end of the bolt, 
the loop of the split-pin remaining outside 
the slot of the nut, and not forced, ham- 
mered, or punched into the slot of the nut 
and mutilated. The length of split-pin 
passing through the opposite slot should 
be equal in length to the diameter of the 
230 



HOW A N AE R OPLA NE IS BUILT 
bolt. This length is split open and the ends 
opened and bent back against the side of 
the nut. 

The loop at the end of the split-pin, 
which should project beyond the nut, 
should not be damaged, as this loop is 
needed to catch hold of should the split- 
pin have to be removed at any time. 

PIPE TESTING. 

Having dealt with the erecting and com- 
pleting of the machine, the oil and petrol 
tanks should be filled up, and a careful 
test made to see that all pipe connections 
are correct, and that there are no leaks of 
any description. 

It is quite possible that one or two pipe 
joints may require attention. Also, petrol 
and oil cocks sometimes require grinding 
in, in which case a small tin of " grinding- 
in paste " will be useful, but extreme care 
must be taken to make sure that all traces 
of this paste are removed after grinding in 
a plug, or any valve. 

TOUCHING UP. 
Having completed erection, it will be 
necessary for the painters and polishers to 
come along and touch up the fittings which 
may have had the enamel damaged, or 
struts which may have become dulled, and 
to do any other polishing or incidental 
work necessary for the proper finishing off 
of the machine. 



HOW AN AEROPLANE IS BUILT 

OVER-ALL INSPECTION. 

The work on the machine having been 
completed, the works inspection depart- 
ment shouldbe duly notified, and a couple 
of men sent to inspect the machine 
thoroughly all over, in detail. To save 
trouble and time, a good plan is for the 
inspectors to have a supply of small red 
" tie-on " labels, which can be tied onto 
any part of the machine requiring atten- 
tion. They should write on the label the 
number and nature of the defect, so that 
when the erectors come to remedy any 
faults, the nature of the defect may at once 
be known to them by referring to the label. 

After the defect has been remedied the 
label must be replaced on the previously 
defective or unfinished part, so that the 
inspector on his return can refer to his 
note-book and the number of the label and 
see that the defect has been remedied. 

The use of this system enables another 
inspector to go through the whole machine, 
and this acts as a double check, as it is 
quite possible that some fault may be 
spotted which has hitherto remained hid- 
den, and further, it causes the first inspec- 
tor to be keener on his inspection, as he 
does not want the second man to notice 

defects which he himself has missed. 

232 



HOW AN AEROPLANE IS BUILT 



THE VARIOUS GADGETS. 

Instruments, such as the compass, air- 
speed indicator, revolution indicator, in- 
clinometer (if any) and various other 
" gadgets," such as gun-mountings and so 
forth, will have been fitted at convenient 
stages in the finishing of the machine. 
Some of them may not be fitted by the 
manufacturer at all, but by the purchaser 
— the Navy or Army, as the case may be, 
or in these days, the Air Force, or later 
on by some private customer or foreign 
Government. In any case, they are not 
produced in our factory, and have nothing 
to do with how we build our aeroplanes, so 
we need not discuss them in detail. They 
have to be fitted as the officials sent down 
by the purchasers wish them to be fitted, 
and we have to follow their instructions. 
So we fix the instruments and gadgets 
accordingly. 

The machine may now be considered 
finished and ready for handing over to the 
aerodrome, whence it will receive its final 
inspection by the A.I.D. and engine tests 
before being flown. 



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With 40' full plates cf "Types of Aeroplanes." 

" A surprisingly useful book." — Westminster Gazette. 

*#* Seven Editions of "The Aeroplane Speaks" have been 
called for in 18 months. The demand for the book has 
grown month by month. 

Order a copy through your bookseller or it may be 
obtained direct from the publishers. 



McBRIDE, NAST & Co., Ltd., 
2 Breams Buildings, London, E.C. 




3 "JDafl DD17SaO^ 



nasm TL671.2.B6 1918X 
How an aeroplane is built,